Domain adaptation of statistical machine translation with domain-focused web crawling Abstract In this paper, we tackle the problem of domain adaptation of statistical machine translation (SMT) by exploiting domain-specific data acquired by domainfocused crawling of text from the World Wide Web. We design and empirically evaluate a procedure for automatic acquisition of monolingual and parallel text and their exploitation for system training, tuning, and testing in a phrase-based SMT framework. We present a strategy for using such resources depending on their availability and quantity supported by results of a large-scale evaluation carried out for the domains of environment and labour legislation, two language pairs (EnglishFrench and English-Greek) and in both directions: into and from English. In general, machine translation systems trained and tuned on a general domain perform poorly on specific domains and we show that such systems can be adapted Lang Resources & Evaluation (2015) 49:147-193 DOI 10.1007 successfully by retuning model parameters using small amounts of parallel indomain data, and may be further improved by using additional monolingual and parallel training data for adaptation of language and translation models. The average observed improvement in BLEU achieved is substantial at 15.30 points absolute. Recent advances in statistical machine translation (SMT) have improved machine translation (MT) quality to such an extent that it can be successfully used in industrial processes (e.g., Flournoy and Duran 2009 ). However, this mostly happens only in specific domains where ample training data is available (e.g., Wu et al. 2008) . Using in-domain data for training has a substantial effect on the final translation quality: the performance of an SMT system usually drops when it is applied to data of a different nature than that on what it was trained (e.g., Banerjee et al. 2010) .. SMT is an instance of a machine learning application which in general works best if the data for training and testing are drawn from the same distribution (i.e., domain, genre, and style). In practice, however, it is often difficult to obtain sufficient amounts of in-domain data (in particular, parallel data required for translation and reordering models) to train a system with good performance for a specific domain. The main problem is usually vocabulary coverage: domain-specific texts typically contain a substantial amount of special vocabulary, which is not likely to be found in texts from other domains ). Additional problems can be caused by divergence in style or genre, where the difference is not only in lexis but also in other linguistic aspects such as grammar.. In order to achieve optimal performance, an SMT system should be trained on data from the same domain, genre, and style as it is intended to be applied to. For many domains, though, in-domain data of a sufficient size to train an SMT system with good performance is difficult to find. Recent experiments have shown that even small amounts of such data can be used to adapt an existing (general-domain) system to the particular domain of interest ). Sometimes, appropriate sources of such data come in the form of existing in-house databases and translation memories (He et al. 2010 ). An alternative option pursued in this paper is to exploit the constantly growing amount of publicly available text on the web, although acquiring data of a sufficient quality and quantity from this resource is a complicated process involving several critical steps (crawling, language identification, cleaning, etc.) .. In this research, we first present a strategy and relevant workflows for automatic webcrawling and cleaning of domain-specific data with limited manual intervention. These workflows are based on open-source tools and have also been deployed as web services in the context of the Panacea 1 research project (Poch et al. 2012) . One advantage of making the tools available as services is that chaining them together enables the building of dynamic and flexible workflows, which can always be improved by integrating new services and/or old legacy systems that may run on different technological platforms. Moreover, the user does not have to deal with technical issues regarding the tools, such as their installation, configuration, or maintenance.. These workflows are then employed to acquire monolingual and parallel data for two domains: environment (env) and labour legislation (lab), and two language pairs: English-French (EN-FR) and English-Greek (EN-EL). The crawled data is further exploited for domain adaptation of a general-domain SMT system in several ways: by domain-specific parameter tuning of the main log-linear model and by adaptation of its components. The evaluation experiments carried out in a total of eight evaluation scenarios (two domains, two language pairs, and both translation directions: to and from English) confirm substantial and consistent improvements in translation quality for all approaches compared to the baseline.. We explain the improvements brought about by analysing the experimental results in detail. In a nutshell, tuning for matching-domain training and test data results in weight vectors that trust (often long) translation table entries. Tuning with and for specific domains (while using generic training data) allows the MT system to stitch together translations from smaller fragments which, in this case, leads to improved translation quality. Such tuning requires only small development sets which can be harvested automatically from the web with minimal human intervention; no manual cleaning of the development data is necessary.. In addition, additional improvements are realised by using monolingual and/or parallel in-domain training data. Adaptation of language models focuses on improving translation fluency and lexical selection for the particular domain. Adaptation of the translation model then aims at reduction of the out-of-vocabulary (OOV) rate and adding domain-relevant translation variants. All the data sets are available via the European Language Resources Association (ELRA). This paper is an extended and updated version of our previous work published as Pecina et al. (2011 Pecina et al. ( , 2012a . Compared to these conference papers, we provide more details of the experiments, full results and a more thorough analysis and description of our findings. Some experiments are new, and not contained in the standalone papers. These include a comparison of various methods for adaptation of language models and translation models (including the state-of-the-art linear interpolation), as well as the comparison of OOV rate (i.e., the ratio of source words unknown to the translation model), language model perplexity measures, and average phrase length in the test set translations (cf . Table 15 ). Compared to the previous papers, the translation quality evaluation in this work is conducted on tokenized and lowercased translations to avoid any bias caused by recasing and detokenization. We also provide much longer descriptions of both related work as well as our data acquisition procedure. Finally, we formulate this paper as one concise yet coherent account of the full range of experiments carried out.. The remainder of the paper is organised as follows. After the overview of related work and description of the state-of-the-art in Sect. 2, we present our web-crawling procedure for monolingual and parallel data in Sect. 3, and the baseline system including its evaluation in Sect. 4. Section 5 is devoted to system adaptation by parameter tuning and Sect. 6 to adaptation of language and translation models. Section 7, which concludes the work, is followed by an Appendix containing formal definitions of the two domains relevant to our work and complete results of the main experiments.. 2 State-of-the-art and related work. In this section, we review the current state-of-the-art in the area of web crawling for monolingual as well as parallel data and briefly describe the main concepts of phrase-based SMT (PB-SMT) and its adaptation to specific domains. In the first main part of the paper (Sect. 4), we focused on a detailed exposition of the pipeline for acquisition of monolingual and parallel data from the World Wide Web. In the second part (Sects. 5-6), we added a thorough investigation of the impact of resources that can be generated using the pipeline, focusing in particular on major established/tried-and-tested approaches to domain adaptation of MT. We Table 14 (env domain only) based on general-domain data for training and tuning (B0), domain-specific parallel data for tuning (P1), additional monolingual data for language models (L2), and additional parallel data for the translation model (C2) Domain adaptation of statistical machine translation 183 discussed the effect of tuning and adaptation on SMT system weights, analysed the learning curves of parameter tuning, OOV rates, perplexity of the test data, and phrase length in translations produced during various stages of adaptation. The pipeline for the acquisition of domain-specific monolingual and parallel texts from the web is based on existing open-source tools for web crawling, text normalisation and cleaning, language identification, duplicate removal, and parallel sentence extraction. It is implemented as easy-to-use web services ready to be employed in industrial scenarios. It requires only limited human intervention for constructing the domain definition and the list of seed URLs, which can easily be tweaked and tuned to acquire texts with high accuracy of 94 %. This pipeline was applied to acquire domain-specific resources for adaptation of a general-domain SMT system. We crawled monolingual and parallel data for two language pairs (English-French, English-Greek) and two domains (environment, labour legislation), which allowed us to perform a large-scale evaluation using a total of eight test scenarios. The acquired data sets are available from ELRA.. Our domain-adaptation experiments focused on the following three components of a PB-SMT model: parameters of the log-linear combination and their optimisation, language model, and translation model. First, we confirmed the observation from previous research that systems trained and tuned on general domain perform poorly on specific domains. This finding is not surprising, but the amount of loss and the fact that it is observed consistently was rather unexpected. The average absolute decrease in BLEU in all the domain-specific evaluation scenarios was 21.82 points (37.86 % relative).. We confirm the results of previous research on tuning-only adaptation. Tuning the general domain-trained systems on specific target domain data recovers a significant amount of the loss. Several hundreds of sentence pairs used as development data improved the BLEU score of the baseline tuned on generaldomain data by 6.64 points absolute (24.82 % relative) on average. A detailed analysis of the model parameters and phrase length distribution in translations of the test data found that a system trained and tuned on general domain data strongly prefers long and few phrases in the output translations, and thus underperforms on specific domains where such phrases do not occur so frequently. In contrast, the same systems tuned on domain-specific data produce output translations from shorter phrases, allow specific reordering and perform significantly and consistently better on specific domains. Importantly, our findings show that the development data does not have to be manually cleaned and corrected, as parameter tuning on the development set (here, using MERT) is quite tolerant to imperfect translations and eventual noise in the development sets. Cross-domain tuning on a different set also offers a good solution when no in-domain development data is available, especially when the domains differ in a similar way. This step has the effect of tweaking the original generaldomain system towards shorter phrases and it does not matter much which different development sets are used.. The experiments with language model adaptation confirmed previous results. Linear interpolation of the general-domain and domain-specific models increased translation quality by a further 4.88 BLEU points absolute (14.95 % relative) compared to the general-domain systems tuned on in-domain development sets on average and significantly outperformed other techniques (concatenation of training data and log-linear combination of the two models). Adaptation of translation models (using 7,000-20,000 acquired sentence pairs) increased BLEU scores by 4.56 points absolute (13.87 % relative) compared to the general-domain systems tuned on in-domain development sets. In this case, linear interpolation and loglinear combination produced similar results. In the combined approach, we observed that the effect of using in-domain monolingual and parallel data is largely independent and does not cancel out when these two types of resources are used at the same time. The final BLEU scores increased by 3.78 points absolute (9.66 % relative) with respect to the language-model-adapted systems, by 8.66 points absolute (26.43 % relative) with respect to the in-domain tuned systems, and by 15.30 points absolute (58.37 % relative) with respect to the general-domain baseline, all on average.. The pipeline for domain-focused web crawling described in this work proved to be very successful in acquisition of domain specific data-both monolingual and parallel. The experiments then showed a high impact of the acquired resources on domain adaptation of MT. We mainly concentrated on parameter tuning and analysis of its effects. Although we did not especially focuse on adaptation of language models and translation models, the acquired data also significantly improved these components and translation quality in general. ecosystems and biodiversity, which mainly refer to pollution control and remediation, legislation well as to resource conservation and management. Texts on natural disasters and their effects on social life are also relevant.

B I O B I I O O B I O O O O O O O O O B I O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Information technology and open innovation: A strategic alignment perspective Advances in information technology (IT) have enabled firms to increasingly rely on open innovation. Although researchers and practitioners are interested in this phenomenon, there is a lack of theoretically driven research on how IT impacts organizational open innovation performance. Drawing on the strategic IT alignment perspective and related literature, we proposed a model to explain the performance of organizational open innovation; i.e., the alignment between IT strategies and the openness of open innovation strategies results in different outcomes for open innovation. Through the analysis of data from 225 firms in China, we found that the alignment between IT flexibility and breadth enhances innovation radicalness and innovation volume, whereas the alignment between IT integration and depth positively affects innovation volume only. Innovation volume and radicalness were found to enhance organizational performance in terms of sales growth. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. The phenomenal advances in information technology (IT) have rendered organizational boundaries so porous that knowledge can be easily transferred inward and outward (Whelan et al. 2010) . As a result, firms need external as well as internal knowledge to compete (Boudreau and Lakhani 2009) . This gives open innovation increasing momentum through management intervention, which results in "the use of purposive inflows and outflows of knowledge to accelerate internal innovation, and expand the markets for external use of innovation, respectively" (Chesbrough et al. 2006, p.1) . Open innovation has been expected to bring significant benefits to firms (Chesbrough 2003a ), e.g., sourcing novel ideas (Soukhoroukova et al. 2012 ), obtaining complementary knowledge for innovation (Huston and Sakkab 2006) , or engaging customers in value co-creation (Conboy and Morgan 2011; Sawhney et al. 2005) . Open innovations will remain relevant in an increasingly competitive and fast-paced environment precipitated by new IT developments. New challenges will arise that require a M a n u s c r i p t M a n u s c r i p t M a n u s c r i p t

O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I O O O O B I I O O O O O O O O O O O O O O B I O O O O O O O O O O B I O O O O O O B I O O O O O O O O O O O O O O O O B I O O O B I O B I O O O O B I O O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Understanding self-organized regularities in healthcare services based on autonomy oriented modeling Abstract Self-organized regularities in terms of patient arrivals and wait times have been discovered in real-world healthcare services. What remains to be a challenge is how to characterize those regularities by taking into account the underlying patients' or hospitals' behaviors with respect to various impact factors. This paper presents a case study to address such a challenge. Specifically, it models and simulates the cardiac surgery services in Ontario, Canada, based on the methodology of Autonomy-Oriented Computing (AOC). The developed AOC-based cardiac surgery service model (AOC-CSS model) pays a special attention to how individuals' (e.g., patients and hospitals) behaviors and interactions with respect to some key factors (i.e., geographic accessibility to services, hospital resourcefulness, and wait times) affect the dynamics and relevant patterns of patient arrivals and wait times. By experimenting with the AOC-CSS model, we observe that certain regularities in patient arrivals and wait times emerge from the simulation, which are similar to those discovered from the real world. It reveals that patients' hospital-selection behaviors, hospitals' service-adjustment behaviors, and their interactions via wait times may potentially account for the self-organized regularities of wait times in cardiac surgery services. In this paper, we have used an AOC-based modeling and simulation approach to characterizing self-organized regularities in cardiac surgery services. In particular, we have described three types of entities, i.e., patient, GP, and hospital, as well as the environment that they reside in and access information from. Based on the identified major impact factors of distance, hospital resourcefulness, wait times, as well as their interaction relationships and local feedback loops, we have derived three types of behavioral rules for patients to make mutual decisions with their GPs on hospital selection and hospitals to adaptively adjust their service rates. Through simulation-based experiments, we have observed that the constructed AOC-CSS model produces a few regularities that are, more or less, similar to those found in the real-world cardiac surgery services. This indicates that the patient-GP mutual hospital selection behavior and its interrelationship with hospital wait times may account for the self-regulating service utilization. It also reveals that the AOC-based modeling approach provides a potentially effective means for explaining the selforganized regularities and investigating emergent phenomena in complex systems. In our future study, it would be promising to study the applications of the presented approach to other real-world complex healthcare services, so as to better understand how self-organized regularities at a systems level emerge from individuals' collective behaviors and their closely coupled interactions.. Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. In general, existing studies related to uncovering the causes of the dynamics and self-organized regularities in patient arrivals and wait times can be classified into two categories: (1) those to empirically identify the effects of multiple factors based on multivariate analysis, and (2) those to characterize the behaviors of healthcare service systems. In this section, we will first review the existing studies. Then, we will briefly introduce AOC, the method that we utilize in this work to model a healthcare service system.

O B I O O O O O O O O O B I O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O B I O B I O O O O O O O O O O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O B I O B I O B I I O O O O O O O O O O O O O O B I O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


A nonadaptive NC checker for permutation group intersection In this paper we design a nonadaptive N C c hecker for permutation group intersection, sharpening a result from Blum and Kannan 3]. This is a consequence of two results. First we s h o w that a nontrivial permutation in the intersection of two given permutation groups (described by lists of generators) can be computed by a n N C a l g orithm with one round of parallel queries to the Group Intersection problem. Next we design a two-round interactive proof system for the complement of the Group Intersection problem, for which the honest prover can be simulated by an NC algorithm with one round of parallel queries to Group Intersection. As a consequence we a l s o h a ve nonadaptive N C c heckers for some related group-theoretic problems.On the technical side, we de ne a generalization of wreath products of permutation groups. This product plays a crucial role in the design of the nonadaptive c heckers. Motivated by the problem of program correctness and reliability, Blum and Kannan introduced in 3] the concept of program checking. Rather than trying to prove a g i v en program correct for all inputs (which is the approach t a k en in the area of Program Veri cation), the approach of program checking is to test and certify a given program for a given input instance. More precisely, a program checker for a given program P is another program that for any instance x of P decides whether the output of P on x is correct or whether P has errors (the formal de nition is given later in Section 2). In the course of checking P on x, the program checker might also query the program P on instances di erent from x. Blum and Kannan in 3] and subsequent researchers, e.g. 4] have s h o wn that this is a fundamental concept. In 3, 4] and several other papers, e cient (in an appropriate sense depending on the problem) checkers have been designed for several nontrivial problems. Interesting connections between program checking and various other concepts in complexity theory like, for example, interactive proof systems and random-self-reducibility 3, 7] have also been established. In particular, the following basic theorem is in 3].. Theorem 1 (Checker Characterization Theorem.) 3] I f a d e cision problem A and its complement have both interactive proof systems, in each of which the honest prover can be simulated in polynomial time with queries to A, then A has a polynomial-time program checker.. Together with known results on interactive proofs 16, 5] it follows that all the problems that are complete for the classes PSPACE, PP or MOD k P h a ve polynomial-time checkers.. It is required of the checker that it be signi cantly more e cient than the program that is being checked. This is a crucial aspect stressed by Blum and Kannan in 3] . In this paper we concentrate on two parameters for measuring the e ciency of a program checker: rst, its running time (not counting the time spent in calls to the program), and next, the number of adaptive calls made by the checker to the program. Ideally, w e w ould like to design a checker minimizing both these parameters. In particular, we consider nonadaptive N C c heckers. I.e., the program checker is a polynomial size circuit of polylogarithmic depth, with query gates at each o f w h i c h a call is made to the program being checked. The additional`nonadaptiveness' property i s t h a t o n e v ery path from an input to the output gate in the circuit, there is at most one query gate. Alternatively, and more suitable for the description of algorithms, such program checkers can be seen as computed by s y n c hronous PRAMs with a polynomial number of processors in polylogarithmic time. Moreover, each processor is allowed to make just one query to the program being checked, at a speci c computation step, all at the same time. The notion of NC checkers was also rst studied in 3]. In fact, in 3] it is shown that every P-complete problem has nonadaptive N C c heckers.. When do problems have nonadaptive N C c heckers? We state below a su cient condition which can be derived easily by adapting the above C h e c ker Characterization Theorem.. Theorem 2 I f a d e cision problem A and its complement have both 2-round interactive proof systems with randomized NC veri ers, in each of which the honest prover can be simulated in NC with nonadaptive queries to A, then A has a nonadaptive NC program checker.. The NC checkers in this paper are essentially designed by applying this theorem. As the main result in this paper, we design a nonadaptive NC program checker for the Group Intersection problem for permutation groups, and some other related permutation group problems. Group Intersection is the following decision problem: given generator sets for two permutation groups A < S n and B < S n for some n, decide if there is a nontrivial permutation in A \ B.. Formally, the language associated with the problem is: GINT = f(A B n)j A B S n and hAi \ h Bi 6 = fidgg:. As our main results, we present an NC algorithm which takes as input an instance (A B n) of GINT and with one round of queries to GINT it computes a nontrivial permutation in hAi \ h Bi (in case one exists). We also design a 2-round interactive protocol for GINT in which the honest prover can be simulated by an NC algorithm with one round of queries to GINT. These results combined with Theorem 2 directly yields a nonadaptive N C c hecker for GINT.. In Blum and Kannan 3] the authors design a polynomial-time, adaptive program checker for a di erent v ersion of this problem. We will refer to the problem they consider as Group Intersection Generators de ned as follows: Given generator sets for two permutation groups A < S n and B < S n for some n, compute a generator set for A \ B.. It is easy to see that Group Intersection Generators is computationally harder problem than Group Intersection (Group Intersection is easily reducible to Group Intersection Generators). However, as we see in this paper, designing a nonadaptive c hecker for Group Intersection is more involved than for Group Intersection Generators. There is a heuristic explanation for this phenomenon given in 3]. It is argued that often it is easier to design a c hecker for an extension of the problem than the problem itself. The extension problem, although usually harder than the problem itself, is easier to check because there is more information produced by the program output for the problem. Notice that this is precisely the case with Group Intersection and Group Intersection Generators (which can be seen as the extension problem in this case). In fact, in 3] the authors highlight this point with a di erent important example, namely, the GCD problem. They show in a few lines that thè Extended GCD' problem has an NC checker, leaving open the question whether GCD has an NC checker. Indeed, only recently an NC checker has been designed for GCD based on nontrivial number theory in 1]. 1 Likewise, since the problem Group Intersection Generators is an extension of Group Intersection, these problems also fall into a similar pattern. Indeed, as we s h o w in this paper, it turns out that we need some nontrivial permutation group theory in order to design a nonadaptive N C c hecker for Group Intersection. In particular, in Section 4. we i n troduce a novel notion of -wreath product of permutation groups generalizing the well-known wreath product 12]. Using -wreath products we are also able to design a nonadaptive N C c hecker also for Group Intersection Generators, improving the result in 3].. We n o w summarize the plan of the paper. In Section 2 we give necessary de nitions, and in Section 3 we s h o w that the search problem for GINT can be solved in parallel with nonadaptive queries. In Section 4 we describe the above-mentioned 2-round interactive protocol for GINT. Finally, in Section 5 we g i v e nonadaptive N C c heckers for Group Intersection Generators and other related group problems. We

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


On multi-granulation covering rough sets Recently, much attention has been given to multi-granulation rough sets (MGRS) and different kinds of multi-granulation rough set models have been developed from various viewpoints. In this paper, we propose four types of multi-granulation covering rough set (MGCRS) models under covering approximation space, where a target concept is approximated by employing the maximal or minimal descriptors of objects in a given universe of discourse U . And then, we investigate a number of basic properties of the four types of MGCRS models, and discuss the relationships and differences among the classical MGRS model and our MGCRS models. Moreover, the conditions for two distinct MGCRS models which produce identical lower and upper approximations of a target concept in a covering approximation space are also studied. Finally, the relationships among the four types of MGCRS models are explored. We find that for any subset X ⊆ U , the lower approximations of X and the upper approximations of X under the four types of MGCRS models can construct a lattice, if we consider the binary relation of inclusion. To enlarge the usage scope of the Pawlak's rough set model [1] , many meaningful extensions have been proposed for various requirements in the past decades, such as the graded rough sets [2] , arbitrary binary relations based rough sets [9, 29] , tolerance or similarity relations based rough sets [30] [31] [32] , rough fuzzy sets and fuzzy rough sets [33] , and variable precision rough sets [34, 35] , etc. As one of the extension models, covering rough sets, which was first proposed by Zakowski [5] , has attracted much attention and induced lots of interesting results [6] [7] [8] [9] 36, 37, [40] [41] [42] . Recently, Yao et al. [4] proposed a framework for the study of covering based rough set approximations, which enables us to reproduce many existing approximation operators and introduce some new approximation operators.. In the viewpoint of Granular Computing [3, 10] , Pawlak's rough set model and most of its extensions are constructed based on only one granular structure, which is induced by a binary relation (a partition or a covering). Thus, one may call those models the single-granulation rough sets. As Qian et al. [12] have mentioned that, in many cases, a target concept is needed to describe concurrently from some independent environments, that is, multi-granulation spaces are needed. Therefore, Qian and Liang [11, 12] introduced the concept of multi-granulation rough sets (MGRS), where the approximations of a set of objects are defined by using multi-equivalence relations. The main difference between single-granulation rough sets and multi-granulation ones lies in that the approximations of a target concept in multi-granulation rough sets are constructed by using multi-distinct sets of information granules. When two attribute subsets in an information system contradict each other or possess an inconsistent relationship, MGRS will show its advantages for knowledge discovery [12] .. By now, much attention has been given to the multi-granulation rough sets. For instance, Qian et al. [13] presented a multi-granulation rough set model based on multiple tolerance relations in incomplete information systems. In [14] , Qian et al. introduced the concept of positive approximation. The positive approximation can be regarded as a special kind of multi-granulation rough set model, in which the granulation structure of a rough set is characterized by using a granulation order, that is, the granulation structure is characterized by a sequence of attribute sets with granulations from coarse to fine. Based on the positive approximation, Qian et al. developed a common accelerator for improving the time efficiency of a heuristic attribute reduction, which provides a vehicle of making algorithms of rough set based feature selection techniques faster. Based on Ref. [13] , Yang et al. [15] further discussed the properties of multi-granulation rough sets in incomplete information systems. Moreover, Yang et al. [16] and Xu et al. [21, 24, 26] constructed multi-granulation rough sets based on the fuzzy approximation space. Yang et al. [17] discussed the hierarchical structures of multi-granulation rough sets and She et al. [28] investigated the topological and lattice-theoretic properties of multi-granulation rough sets. Liang et al. [39] introduced an efficient rough feature selection algorithm with a multi-granulation view. Liu et al. [18, 19] introduced the concepts of multi-granulation covering rough sets and multi-granulation covering fuzzy rough sets in a covering approximation space. Lin et al. [20] discussed two kinds of neighborhood-based multi-granulation rough sets and three kinds of covering based multi-granulation rough sets [43] . Xu et al. [22, 25, 27] constructed three kinds of multi-granulation rough sets based on the tolerance, ordered and generalized relations respectively. Qian et al. [44] developed the multi-granulation decision-theoretic rough set and proved that many existing multi-granulation rough set models can be derived from the multi-granulation decision-theoretic rough set framework.. As an extension of our previous work [18] , the purpose of this paper is to further generalize the classical multigranulation rough sets to covering environment. Through combining the multi-granulation rough sets with covering rough sets, we aim to solve the limitation of classical multi-granulation rough sets induced by equivalence relations. To define the approximations of a target concept in the multi-granulation covering environment, we respectively employ the maximal and minimal descriptors of objects in a given universe of discourse U . For any subset X ⊆ U and object x ∈ U , we first respectively define the type-1 and type-2 approximations (including low and upper approximations) of X by using the intersection and union of all elements in the minimal descriptor of x. Second, the type-3 and type-4 approximations of X are respectively defined based on the intersection and union of all elements in the maximal descriptor of x. Correspondingly, we can obtain four types of multi-granulation covering rough set (MGCRS) models under a covering approximation space. The basic properties of the four types of MGCRS models, and the relationships among the classical MGRS model and our MGCRS models are discussed. Moreover, the conditions for two distinct MGCRS models which produce identical lower and upper approximations of a target concept in a covering approximation space are also studied. Finally, the relationships among the four types of MGCRS models are explored.. The remainder of this paper is organized as follows. The next section deals with some preliminary concepts and properties regarding the Pawlak's rough sets, covering rough sets and multi-granulation rough sets. In Section 3, we introduce four types of multi-granulation covering rough set models and investigate the basic properties of them. Moreover, based on the concept of reduct of a covering, we give the sufficient conditions for two different MGCRS models to produce identical lower and upper approximations of a target concept. In Section 4, we investigate the relationships among the four types of MGCRS models. Finally, Section 5 concludes the paper. To extend the application domain of MGRS, this paper has introduced four types of multi-granulation covering rough set models and studied the basic properties of these models. We have shown that our MGCRS models are generalized versions of MGRS models. Moreover, we have given the sufficient conditions for two distinct MGCRS models which produce identical lower and upper approximations of a given concept in a covering approximation space. Finally, the relationships among various MGCRS models were discussed. We have shown that for any X ⊆ U , the set of all those lower and upper approximations equipped with the binary relation ⊆ of inclusion, can construct a lattice.. In the future work, we shall further discuss other aspects of MGCRS, for example, the topological properties of MGCRS, or MGCRS in fuzzy settings.

O B B B I O O O O O O O B B I O O O O O B O O O O O O O O O O O O O O O O O B B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O B I O O O O O O O O B I O O O O O O O O O B I O O O O O B I O O O O O O O O O O B B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B B I O O O O O O O O O O O O O O O O O O O O B I O B O O O O O O O O O O O B B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B I O O O O O O O O O O O O O O O O O B B I O O O O O O O O O O O O O O O B B I O O O O O O O O O O O O B B I O O O O O O O O O O O O O B O O O O O O O O O O B B B I O B B O B I O O B O O O O O O O O O O O B B I O O O O B O B B I O O O O O O O O O O O O B B I O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B I O B O O O O B B I O B B I O O O O O O O O B B I O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I B B I O B B I O O O O O O O O B B O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Suppliers selection in the presence of both cardinal and ordinal data Traditionally, supplier selection models are based on cardinal data with less emphasis on ordinal data. However, with the widespread use of manufacturing philosophies such as Just-In-Time (JIT), emphasis has shifted to the simultaneous consideration of cardinal and ordinal data in supplier selection process. To select the best suppliers in the presence of both cardinal and ordinal data, this paper proposes an innovative method, which is based on Imprecise Data Envelopment Analysis (IDEA). A numerical example demonstrates the application of the proposed method. Managing the purchasing task in the supply chain has been a challenge in the last decade for many corporations. The need to gain a global competitive edge on the supply side has increased substantially. Particularly for companies who spend a high percentage of their sales revenue on parts and material supplies, and whose material costs represent a larger portion of total costs, savings from supplies are of particular importance.. Moreover, the emphasis on quality and timely delivery in today ' s globally competitive marketplace adds a new level of complexity to outsourcing and supplier selection decisions. These, strongly urge for a more systematic and transparent method to purchasing decision making, especially regarding the area of supplier selection. Selecting the right suppliers significantly reduces the purchasing cost and improves corporate competitiveness, which is why many experts believe that the supplier selection is the most important activity of a purchasing department. Supplier selection is the process by which suppliers are reviewed, evaluated, and chosen to become part of the company ' s supply chain. Shin et al. (2000) argue that several important factors have caused the current shift to single sourcing or a reduced supplier base. First, multiple sourcing prevents suppliers from achieving the economies of scale based on order volume and learning curve effect. Second, multiple supplier system can be more expensive than a reduced supplier base. For instance, managing a large number of suppliers for a particular item directly increases costs, including the labor and order processing costs to managing multiple source inventories. Meanwhile multiple sourcing lowers overall quality level because of the increased variation in incoming quality among suppliers. Third, a reduced supplier base helps eliminate mistrust between buyers and suppliers due to lack of communication. Fourth, worldwide competition forces firms to find the best suppliers in the world.. Traditionally, supplier selection models are based on cardinal data with less emphasis on ordinal data. However, with the widespread use of manufacturing philosophies such as Just-In-Time (JIT), emphasis has shifted to the simultaneous consideration of cardinal and ordinal data in supplier selection process. This paper proposes a method for selecting the best suppliers in the presence of both cardinal and ordinal data. The objective of this paper is to propose an innovative method for selecting suppliers in the conditions that both ordinal and cardinal data are present (without relying on weight assignment by decision makers). This paper proceeds as follows. In Section 2, literature review is presented. In Section 3, the method that selects the suppliers is introduced. Numerical example and concluding remarks are discussed in Sections 4 and 5, respectively. Many practitioners and researchers have presented the advantages of supply chain management. In order to increase the competitive advantage, many companies consider that a well-designed and implemented supply chain system is an important tool. Under this condition, building on the closeness and long-term relationships between buyers and suppliers is critical success factor to establish the supply chain system. Therefore, supplier selection problem becomes the most important issue to implement a successful supply chain system. To select the most efficient suppliers in the conditions that both ordinal and cardinal factors are present, a methodology was introduced.. The results of this paper can be applied from both a buyer ' s and supplier ' s perspective. The buyer can use it as a tool in selecting the "best" supplier. The supplier can use these results from a marketing perspective. A specific supplier, who achieves a high mean score, when compared to the other suppliers, can use these results for promoting their product. On the other hand, if a particular supplier is poorly performing, then the supplier can use the analysis for benchmarking purposes. This result may mean that the supplier must provide better performance levels at the same input.. The problem considered in this study is at initial stage of investigation and much further researches can be done based on the results of this paper. Some of them are as follows: Similar research can be repeated for dealing with ordinal data and bounded data by fuzzy sets. The other research can be accomplished for suppliers ranking in the presence of qualitative data, imprecise data, and stochastic data. Other potential extension to the methodology includes the case that some of the suppliers are slightly non-homogeneous.. One of the assumptions of all the classical models of DEA is based on complete homogeneity of DMUs (suppliers), whereas this assumption in many real applications cannot be generalized. In other words, some inputs and/or outputs are not common for all the DMUs occasionally. Therefore, there is a need to a model that deals with these conditions. To compare the results of performance of proposed method with fuzzy DEA will be another research topic.

O O O O O O O B I I I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O B I O O O O O O O O O O O B I I I O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O B I O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Finite Variability Interpretation of Monadic Logic of Order We consider an interpretation of monadic second-order logic of order in the continuous time structure of finitely variable signals. We provide a characterization of the expressive power of monadic logic. As a by-product of our characterization we show that many fundamental theorems which hold in the discrete time interpretation of monadic logic are still valid in the continuous time interpretation. In the recent years systems whose behavior change in the continuous (real) time were extensively investigated. Hybrid and control systems are prominent examples of real time systems.. A run of a real time system is represented by a function from non-negative reals into a set of values -the instantaneous states of a system. Such a function will be called a signal. Usually, there is a further restriction on behavior of continuous time systems. For example, a function that gives value q 0 for the rationals and value q 1 for the irrationals is not accepted as a 'legal' signal.. A requirement that is often imposed in the literature is that in every bounded time interval a system can change its state only finitely many times. This requirement is called a finite variability (or a non-Zeno) requirement. A function from the non-negative real into a set Σ that satisfies this requirement is called a finitely variable signal. If in addition such function x satisfies the requirement that for every t there is ǫ > 0 such that x is constant on [t, t+ǫ), then it is called a right continuous signal. It is clear that finite variability and right continuous requirements are not metric requirements.. Recall that the language L < 2 of monadic second order logic of order contains individual variables, second order variables and the binary predicate <. In the discrete time structure ω (this structure will be defined precisely in section 3), the individual variables are interpreted as natural numbers, the second order variables as monadic predicates (monadic functions from the natural numbers into the booleans), and < is the standard order on the set of natural numbers.. A monadic formula φ(X) with one free predicate variable X defines a set of ω-strings over {0, 1} that satisfies φ. There exists a natural one-one correspondence between the set of ω-strings over the alphabet {0, 1}. n and the set of n-tuples of monadic predicates over the set of natural numbers. With a formula ψ(X 1 , . . . , X n ) the set of ω-strings which satisfies ψ through this correspondence can be associated. Such a set of ω-strings is called the ω-language definable by ψ. So, monadic logic can be considered as a formalism for the specification of the behavior (set of runs) of discrete time systems. This logic is accepted as a kind of an universal formalism among decidable formalisms for the specification of discrete time behavior [13] .. In this paper we consider interpretations of monadic logic in the continuous time structures of the finitely variable signals and the right continuous signals. In these structures the individual variables range over the non-negative real numbers, the second order variables range over the finitely variable (respectively, right continuous) boolean signals, and < is the standard order relation on the set of real numbers. Similar to the discrete case, monadic logic can be considered as a formalism for the specification of the behavior of continuous time systems. Note that metric properties of reals cannot be specified in this logic.. We provide (see Theorem 1) a characterization of signal languages definable in the monadic logic of order. The result is significant due to the fact that many specification formalisms for reasoning about real time which were considered in the literature can be effectively embedded in L < 2 . In [10] we illustrated the expressive power of L < 2 by providing meaning preserving compositional translations from Restricted Duration Calculus [4] , Propositional Mean Value Calculus [5] and Temporal Logic of Reals -TLR [3] into the first-order fragment of L < 2 . We apply Theorem 1, for the analysis of a number of fundamental problems. First, as an immediate consequence of our main result we obtain the decidability of L < 2 under finitely variable and right continuous interpretations. These decidability results were obtained in [9, 10] by the method of interpretation [7] . We reduced in [9, 10] these decidability problem to the decidability problem for L < 2 under F σ interpretation. In F σ interpretation the monadic predicate variables range over the countable unions of closed subsets of reals. The decidability of L < 2 under under F σ interpretation was shown to be decidable in [7] .. Second, we show that under finitely variable and right continuous interpretations the existential fragment of L < 2 is expressive complete, i.e. for every L < 2 formula φ there is an equivalent formula of the form ∃X 1 . . . ∃X n ψ, where ψ is a first-order monadic formula.. Then we reconsider two fundamental problems of Classical Automata The-ory: (1) Automata characterization of the L < 2 definable languages and (2) The uniformization problem.. The classical result of Büchi provides an automata theoretical characterization of the L < 2 definable languages It says that an ω-language is definable by a monadic formula (under the discrete interpretation) iff it is accepted by a finite state automaton.. Let φ(X, Y ) be a formula such that ∀X∃Y φ holds. The uniformization problem for φ is to find a finite state input-output automaton (transducer) such that the function F computable by the automata satisfies ∀X.φ(X, F (X)). The uniformization problem for the monadic second order theory of order of the structure ω was solved positively by Büchi and Landweber [2] .. We check whether these classical results can be extended to continuous time. In [11] automata that accept finitely variable languages were defined. It was announced there that a finitely variability language is definable in monadic logic iff it is accepted by a finite state automata. Here we show that this theorem is a consequence of Theorem 1. In [11] it was announced that the uniformization problem has a positive solution in the continuous time. We found a bug in our proof. In the last section we show that the failure of the uniformization is a consequence of Theorem 1.. The rest of this paper is organized as follows. In Section 2 terminology and notations are fixed. In Section 3 the syntax and semantics of monadic second order logic of order is recalled. Theorem 1 provides reductions between definable ω-languages and definable signal languages; it is stated in Section 4. In Section 5 we collect some simple lemmas and in Section 6 we prove the Theorem 1. Section 7 gives some important corollaries.

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Geometric mechanics and the dynamics of asteroid pairs The purpose of this paper is to describe the general setting for the application of techniques from geometric mechanics and dynamical systems to the problem of asteroid pairs. It also gives some preliminary results on transport calculations and the associated problem of calculating binary asteroid escape rates. The dynamics of an asteroid pair, consisting of two irregularly shaped asteroids interacting through their gravitational potential is an example of a full body problem or FBP in which two or more extended bodies interact.One of the interesting features of the binary asteroid problem is that there is coupling between their translational and rotational degrees of freedom. General FBPs have a wide range of other interesting aspects as well, including the 6-DOF guidance, control, and dynamics of vehicles, the dynamics of interacting or ionizing molecules, the evolution of small body, planetary, or stellar systems, and almost any other problem where distributed bodies interact with each other or with an external field. This paper focuses on the specific case of asteroid pairs using techniques that are generally applicable to many other FBPs. This particular full 2-body problem (F2BP) concerns the dynamical evolution of two rigid bodies mutually interacting via a gravitational field. Motivation comes from planetary science, where these interactions play a key role in the evolution of asteroid rotation states and binary asteroid systems.The techniques that are applied to this problem fall into two main categories. The first is the use of geometric mechanics to obtain a description of the reduced phase space, which opens the door to a number of powerful techniques such as the energy-momentum method for determining the stability of equilibria and the use of variational integrators for greater accuracy in simulation. Secondly, techniques from computational dynamical systems are used to determine phase space structures important for transport phenomena and dynamical evolution. Full body problems (FBPs) are concerned with the dynamical interaction between two or more distributed bodies. This fascinating class of problems has many interesting open questions and touches on numerous important issues in science and engineering. Examples include binary asteroids, the evolution and dynamics of the Earth-Moon system, the dynamics and control of a high-performance aircraft, reaction and ionization of molecules, interactions and collisions between galaxies, stability and control of underwater vehicles, rendezvous and docking of space vehicles, fine pointing control of a space-based telescope, etc. Geometric mechanics and dynamical systems theory along with appropriate computational and geometric control techniques, provide a unified approach to the analysis and simulation of these problems.. There are many examples in which geometric mechanics methods have been used for this general class of problems. Two examples are the work of Krishnaprasad and Marsden [1987] concerning the use of reduction and stability methods for rigid bodies with flexible attachments and also the work of Krupa et al. [2001] on the use of the energy-momentum method for tethered satellites.. The Binary Asteroid Problem. In this paper we focus on the dynamics of binary asteroids in the context of F2BPs. This problem concerns the dynamics of two spatially extended bodies that interact via their mutual gravitational fields. An example of a motivating goal is the accurate estimation of ejection, collision, and transport rates, accounting fully for coupling between the rotational and translational states of the bodies. We put this problem into the context of systematic approaches to determine the stability of relative equilibria as well as the computation of phase space structures, such as periodic orbits, quasi-periodic orbits, and the division of phase space into regions of regular and chaotic motion. This context allows one to bring to bear powerful computational transport techniques, such as set oriented methods and lobe dynamics. As we shall review below, there is already quite a bit known about relative equilibria in the binary asteroid problem; we refer to Scheeres [2003] for further information. However, rather little has been done on the energy-momentum method (and its converse) for relative equilibria as well as 1. Geometric Mechanics and Reductions of the F2BP. As hinted at already and explained further in, for example, Bloch [2003] , Marsden and Ratiu [1999] and Marsden [1992] , geometric mechanics has had enormous successes in many areas of mechanics. Previous investigations in the FBP, however, have been piecemeal at best and have missed using, for example, the powerful energy-momentum method and its converse for relative equilibria, as well as the use of geometric phases. For example, the converse of the energymomentum method, due to Ratiu [1994, 1996] allows one to study the destabilizing effect of dissipation and body deformations for relative equilibria that are gyroscopically stabilized on the linear level (that is, one has a saddle point in the augmented energy, but the system eigenvalues are on the imaginary axis, so one cannot easily infer stability or instability in the nonlinear system).

B I O O B O B I O O O O O O O O O O O O O O O O O B I O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Recognition and Classification of Histones Using Support Vector Machine Histones are DNA-binding proteins found in the chromatin of all eukaryotic cells. They are highly conserved and can be grouped into five major classes: H1/H5, H2A, H2B, H3, and H4. Two copies of H2A, H2B, H3, and H4 bind to about 160 base pairs of DNA forming the core of the nucleosome (the repeating structure of chromatin) and H1/H5 bind to its DNA linker sequence. Overall, histones have a high arginine/lysine content that is optimal for interaction with DNA. This sequence bias can make the classification of histones difficult using standard sequence similarity approaches. Therefore, in this paper, we applied support vector machine (SVM) to recognize and classify histones on the basis of their amino acid and dipeptide composition. On evaluation through a five-fold cross-validation, the SVMbased method was able to distinguish histones from nonhistones (nuclear proteins) with an accuracy around 98%. Similarly, we obtained an overall >95% accuracy in discriminating the five classes of histones through the application of 1-versus-rest (1-v-r) SVM. Finally, we have applied this SVM-based method to the detection of histones from whole proteomes and found a comparable sensitivity to that accomplished by hidden Markov motifs (HMM) profiles.

O O B O B O B I I B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O B I I O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O


On Composing Stream Applications in Peer-to-Peer Environments Abstract-Stream processing has become increasingly important as many emerging applications call for continuous real-time processing over data streams, such as voice-over-IP telephony, security surveillance, and sensor data analysis. In this paper, we propose a composable stream processing system for cooperative peer-to-peer environments. The system can dynamically select and compose stream processing elements located on different peers into user desired applications. We investigate multiple alternative approaches to composing stream applications: 1) global-state-based centralized versus local-state-based distributed algorithms for initially composing stream applications at setup phase. The centralized algorithm performs periodical global state maintenance while the distributed algorithm performs on-demand state collection. 2) Reactive versus proactive failure recovery schemes for maintaining composed stream applications during runtime. The reactive failure recovery algorithm dynamically recomposes a new stream application upon failures while the proactive approach maintains a number of backup compositions for failure recovery. We conduct both theoretical analysis and experimental evaluations to study the properties of different approaches. Our study illustrates the performance and overhead trade-offs among different design alternatives, which can provide important guidance for selecting proper algorithms to compose stream applications in cooperative peer-to-peer environments. This paper has presented a composable stream processing system for cooperative P2P environments. To the best of our knowledge, this is the first work that studied composing stream applications in P2P environments. Specifically, this paper proposes and analyzes a set of efficient algorithms for two key problems in composing stream applications: 1) the global-state-based centralized algorithm versus the localstate-based distributed algorithm for the initial service composition problem, and 2) the reactive failure recovery algorithm versus the proactive failure recovery algorithm for the dynamic failure recovery problem. While finding the optimal solutions for both problems is NP-hard, the proposed approximation algorithms can achieve much better performance than other alternative heuristics under different workloads and system conditions. Our comparison study also reveals the key factors that can affect the trade-offs among different design alternatives. Our results can provide important guidance for adaptively selecting proper algorithms to compose stream processing applications in dynamic P2P environments. W ITH the popularity of peer-to-peer (P2P) file sharing systems [1] , P2P systems have drawn much research attention. One salient advantage of P2P systems is that they can aggregate a tremendous amount of resources in a failure-resilient and cost-efficient fashion. Previous work has addressed the problems of scalable data lookup (e.g., [28] , [31] , [26] ), incentive engineering (e.g., [22] ), and anonymity preservation (e.g., [35] ) for providing efficient P2P data sharing. Inspired by P2P file sharing systems, researchers have proposed other P2P applications such as P2P streaming systems (e.g., [33] , [17] , [20] , [8] ) and P2P storage systems (e.g., [4] ). In this paper, we focus on studying the problem of providing stream processing applications in cooperative P2P environments [8] . A cooperative P2P system consists of responsible peer users who honestly share resources with each other for the common good of everyone, such as enterpise P2P systems. The P2P streaming system can effectively support many stream applications such as voice-over-IP (VoIP) telephony, sensor data analysis, and security surveillance. Fig. 1 shows a VoIP application where the speaker's audio stream is processed by a language translation service and a speech transcription service before reaching the receiver. In this paper, a service is a self-contained application unit providing a certain stream processing function.. Although streaming systems have been studied in conventional distributed environments, P2P streaming systems must meet new challenges: 1) Heterogeneity: P2P systems consist of heterogeneous end-hosts, which implies that stream applications should be adaptive to fill the gap between senders and receivers. 2) Decentralization: P2P systems are fully decentralized where services can have multiple instances dispersed on different peers. 3) Churn: P2P systems allow peers to arbitrarily leave or join the systems, which makes long-lived stream applications prone to failures. To address these challenges, we propose a composable streaming system that can dynamically compose stream applications from selected service instances based on the user's function, resource, and quality-of-service (QoS) requirements. Although composable service infrastructures have been proposed under different research context (e.g., [25] , [10] , [21] , [23] , [13] , [7] ), it is still an open problem to provide an efficient composable streaming system that can meet the new challenges of P2P environments.

O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O B O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Practical use of a latent semantic analysis (LSA) model for automatic evaluation of written answers This paper presents research of an application of a latent semantic analysis (LSA) model for the automatic evaluation of short answers (25 to 70 words) to open-ended questions. In order to reach a viable application of this LSA model, the research goals were as follows: (1) to develop robustness, (2) to increase accuracy, and (3) to widen portability. The methods consisted of the following tasks: firstly, the implementation of word bigrams; secondly, the implementation of combined models of unigrams and bigrams using multiple linear regression; and, finally, the addition of an adjustment step after the score attribution taking into consideration the average of the words of the answers. The corpus was composed by 359 answers produced according to two questions from a Brazilian public university's entrance examination, which were previously scored by human evaluators. The results demonstrate that the experiments produced accuracy about 84.94 %, while the accuracy of the two human evaluators was about 84.93 %. In conclusion, it can be seen that the automatic evaluation technology shows that it is reaching a high level of efficiency. Our focus was to develop a technology allowing practical use of an LSA model for automatic evaluation of written answers to open-ended questions. We worked in four directions: (1) to create a co-occurrence model of unigrams and bigrams and use it as the baseline for the LSA model-it was verified that LSA model was superior in both approaches; (2) to combine bigrams with LSA to test its performance, since traditional models only use unigrams. We observed that this combination produced better results with the conceptual answers, but did not have any significant impact on the evaluation of the argumentative answers. In both sets of answers, the use of bigrams did not bring any improvement compared to unigrams; (3) to adjust the LSA scores based on the number of words per answer. The implementation of this penalty factor caused an enhancement of 8 to 10 % on the accuracy indexes; (4) to analyze the distribution of the LSA attributed scores against the human evaluators' scores, having found 79 % of coincident or close answers. The results show that LSA models can be used to refine results from methods based solely on n-grams, with the best outcomes depending on parameters calibration and on the applicability domain. The experiments provided an accuracy index of 84.94 % compared to human evaluators, whereas the accuracy between those evaluators was of 84.93 %. In this study's domain, the technology presented results close to human evaluators' results, showing actual application potential in automatic evaluation systems in virtual learning environments. 1 The rank of a matrix M is the dimension of row or column space of M An automatic evaluation system is a computational technology used to analyze and rate written texts. Studies on this technology reveal how computers may be used to measure students' learning degree [1] . Though research on automatic evaluation of written answers has been going on since the 1960 [2] [3] [4] , it has been only since the late 1990s that new models and methods of natural language processing have demonstrated higher accuracy level for practical applications [1, 5, 6] , and more recent research shows accuracy closer to that of human evaluators [7] .. The majority of research on automatic evaluation uses n-grams approaches within different applications [4, 8, 9] . More recently, regarding the automatic evaluation of written answers, there are some promising approaches that use the latent semantic analysis (LSA) model [4, 8, [10] [11] [12] . In these approaches, we find results ranging from 0.63 to 0.86, which are measurements of the correlation between *Correspondence: jcas@ufpa.br 1 Faculdade de Matemática, UFPa, Rua Augusto Corrêa s/n, Belém, Brazil Full list of author information is available at the end of the article scores attributed by LSA models and those attributed by human evaluators [10, 13, 14] .. In this scenario, LSA models called bag-of-words (not concerned with word order) are adequate for many applications [15, 16] . More recent works investigate models which combine LSA with other techniques, such as word syntactic neighborhood analysis, a model that considers the arithmetic means between n-grams and LSA [4, 8, 17] , or that combines knn algorithms with LSA [18] . In order to make the model more robust and possibly to enhance its accuracy, we work with bigrams of words because they preserve dependent relations between them that represent the sequence of words within the answers, thus surpassing the bag-of-words model.. Though some may argue that the use of bigrams with LSA is not viable for some applications due to size limitations on the initial matrices (the matrixes were around 1805 × 229), we find it possible to apply bigrams to this domain, since they are composed of short written answers (averaging 25 to 70 words) to open-ended questions from a higher education institution's exam. Furthermore, we only count those bigrams that appear at least in two answers, as to avoid a high number of null entries in the initial matrix.. In sum, our goal is to develop technology for an LSA system with more robustness, accuracy, and portability:. • Robustness: a traditional LSA model is not concerned with the order of the words within the text, thus being vulnerable to errors: an informed student may well deceive the system [10] . The use of bigram aims to make the system immune to this type of threat and therefore more viable.. • Accuracy: the correlation between an LSA system and a human evaluator may be high, it can be compared with correlation between two humans evaluator. This is a way to assert the efficiency of an LSA model, even though there still is no definitive research on the matter.. • Portability: the accuracy of an LSA model is largely dependent on the parameters of its applicability domain (type and size of corpus), making it difficult to apply successful experiments to new domains [10, 11, 19] . Calibration takes into account: preprocessing, local and global weighing, dimensionality, and the function of similarity.. The proposed LSA model estimates the scores of each answer with a six-step procedure: (1) preprocessing, (2) weighing, (3) singular value decomposition (SVD), (4) rating, (5) adjustments, and (6) accuracy. We then compare the LSA scores with those given by the human evaluators to calculate the accuracy between them.. An LSA model can be viewed as an improvement over a model based solely on n-grams because it has a more precise measure of similarity. LSA also captures contextual use of words, synonymy, etc. To demonstrate this fact, we tested a baseline model based on unigrams and bigrams combined with multiple linear regressions. This model reached an accuracy level of 78.74 %, while the LSA model reached 84.94 %. With these numbers, we can assert that this technology is efficient enough for practical application.. In this work, we propose an automatic evaluation approach for discursive questions. This system is acceptable to practical uses if its performance is similar to the human evaluators [14] . We believe that these may be innovative technologies for the virtual learning environment: we are employing this technique in a virtual learning environment of the Federal University of Pará, a college with 60,000 students from technical education through undergraduate to post-graduation. Further, this application is advantageous as an instant score feedback for large groups of students (hundreds or thousands), freeing the teacher from manual correction and enabling him or her to pay closer attention to lower scoring students. This work is organized as an introduction plus six sections: the second presents a brief description of LSA, the third presents the corpus used in the work, the fourth presents the LSA model, the fifth presents the model's calibration process, the sixth presents a discussion of the results, and the seventh presents conclusions and future research.

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