ppxscal/embedding_network huggingface dataset:
Lower bounds on the minus domination and k-subdomination numbers
Authors: Liying Kang, Hong Qiao, Erfang Shan, Dingzhu Du
Venue: Theoretical Computer Science (2003)

A three-valued function f defined on the vertex set of a graph G=(V,E), f:V → {-1,0,1} is a minus dominating function if the sum of its function values over any closed neighborhood is at least one. That is, for every v ∈ V, f(N[v]) ≥ 1, where N[v] consists of v and all vertices adjacent to v. The weight of a minus function is f(V)= Σv ∈ V f(v). The minus domination number of a graph G, denoted by γ-(G), equals the minimum weight of a minus dominating function of G. In this paper, sharp lower bounds on minus domination of a bipartite graph are given. Thus, we prove a conjecture proposed by Dunbar et al. (Discrete Math. 199 (1999) 35), and we give a lower bound on γks(G) of a graph G.
Empirical Study of Inter-Arrival Packet Times and Packet Losses
Authors: Takayuki Kushida, Yoshitaka Shibata
Venue: Proceedings of the 22nd International Conference on Distributed Computing Systems (2002)

A packet switched network such as the Internet provides only the best-effort service for users. Recent studies for the characterisitics of the packet arrival on the packet switched network have shown a self-similar property with a long-range dependence, and also show the heavy-tailed distribution. This paper investigates the end-to-end performance of the Internet empirically. It focuses on the inter-arrival process of packets and the property of the packet loss between end-to-end hosts. We show that both the inter-arrival process and loss events have self-similar with a long-range dependence property. The inter-arrival process of packetshas the heavy-tailed distribution which sums up the difference of all queues in intermediate routers.
Application of max-plus algebra to biological sequence comparisons
Authors: J.-P. Comet
Venue: Theoretical Computer Science (2003)

The classical algorithms to align two biological sequences (Needleman and Wunsch and Smith and Waterman algorithms) can be seen as a sequence of elementary operations in (max, +) algebra: each line (viewed as a vector) of the dynamic programming table of the alignment algorithms can be deduced by a (max, +) multiplication of the previous line by a matrix. Taking into account the properties of these matrices there are only a finite number of nonproportional vectors. The use of this algebra allows one to imagine a faster equivalent algorithm. One can construct an automaton and afterwards skim through the sequence databank with this automaton in linear time. Unfortunately, the size of the automaton prevents using this approach for comparing global proteins. However, biologists frequently face the problem of comparing one short string against many others sequences. In that case this automaton version of dynamic programming results in a new algorithm which works faster than the classical algorithm.
The Variety of An Assortment
Authors: Stephen J. Hoch, Eric T. Bradlow, Brian Wansink
Venue: Marketing Science (1999)

Consumers rank variety of assortment right behind location and price when naming reasons why they patronize their favorite stores. Consumers care about variety because they are more likely to find what they want when going to a store that offers more varied assortments. When tastes are not well formed or are dynamic, perceived variety matters even more because of the desire to become educated about what is available while maintaining flexibility. Variety perception also matters when the variety-seeking motive operates. Retailers care about variety because customers value variety. Therefore, it is important to understand how people perceive the variety contained in an assortment and how these perceptions influence satisfaction and store choice. Remarkably, except for a recent study by Broniarczyk et al. (1998), there has been no research aimed at understanding the variety perception process itself. We offer a general mathematical model of variety based on the complete information structure of an assortment, defined both by the multiattribute structure of the objects and their spatial locations. We impose a psychologically plausible set of restrictions on the general model and obtain a class of simpler estimable models of perceived variety. We utilize the model to develop assortments that vary widely in terms of their information structure and study the influence of three factors on variety perceptions: (a) information structure of each assortment (i.e., the attribute level differences between objects); (b) level of organization of the objects and hence their relative spatial positions; and (c) task orientations, promoting either analytic or holistic processing. We also investigate the influence of variety perception and organization on stated satisfaction and store choice. To summarize our major findings: 1. Information structure has a big impact on variety perceptions, though diminishing returns accompany increases in the number of attributes on which object pairs differ. 2. People are more influenced by local information structure (adjacent objects) than nonlocal information structure. Proximity matters. 3. Organization of the display can either increase or decrease variety perceptions. When people engage in analytic processing, organized displays appear to offer more variety. When processing is holistic, random displays are seen as more varied. 4. Both variety perceptions and organization drive stated satisfaction and store choice. People are more satisfied withand likely to choose stores carrying those assortments that are perceived as offering high variety and that are displayed in an organized rather than random manner. Our work provides a basic framework for thinking about variety. By helping retailers to understand the factors that drive variety perception, it may be possible to design more efficient, lower cost assortments without reducing variety perceptions and the probability of future store visits.
Recursive-ascent parsing
Authors: Larry Morell, David Middleton
Venue: Journal of Computing Sciences in Colleges (2003)

A new procedural method of implementing bottom-up parsing called recursive-ascent parsing is defined. In recursive-ascent, procedures are used to implement bottom-up parsing in a manner similar to the way procedures are used in recursive-descent to implement top-down parsing. We hypothesize that this makes bottom-up parsing techniques more readily accessible to students. The paper illustrates recursive-ascent techniques and shows how to develop these as a generalization of recursive-descent. A hand-developed recursive-ascent parser is compared to a bottom-up parser generated by yacc.
Mission Planning for Synthetic Aperture Radar Surveillance
Authors: David M. Panton, Anita W. Elbers
Venue: Interfaces (1999)

The Microwave Radar Division of the Defence Sciences and Technology Organisation employs synthetic aperture radar to obtain high-resolution images of selected ground targets. It uses this device, mounted on an aircraft, to scan up to 20 rectangular regions called swaths to obtain images with resolutions down to one meter. Missions consisting of a designated sequence of swaths and flight paths are planned using mapping software. Previously DSTO had been determining the best tours for missions by visually tracking possible swath sequences from a starting base to an ending base. This method was time consuming and did not guarantee optimality interms of distance traveled. We developed optimization software tools to plan mission tours more efficiently. DSTO can now plan missions with up to 20 swaths in a few seconds, rather than the hour it took using the visual approach. Proposed tour lengths show an average improvement of 15 percent over those manually produced. The software incorporates methods for dealing with the operational problems of no-fly zones and shadowing associated with images.
Mr.Web: an automated interactive webmaster
Authors: Andrea Lockerd, Huy Pham, Taly Sharon, Ted Selker
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This paper describes a system, Mr.Web, designed to interact with users over email to create and update Web pages. Our goal is that users interact with Mr.Web as if it were a human Webmaster. We collected 325 examples of people writing email requests to a Webmaster, and used this to generate the semantics of Mr.Web's email parser. The results of the survey indicate that the limited context of a Webmaster gives us a reasonable subset of the natural language processing (NLP) problem. This paper explains the system design, user study results, and plans for future work.
The stability problem for fuzzy bidirectional associative memories
Authors: Qiansheng Cheng, Zhou-Tian Fan
Venue: Fuzzy Sets and Systems (2002)

The fuzzy bidirectional associative memories (FBAMs) are studied in this paper. It is shown that any FBAM based on the S-T composition is globally stable if both S and T are triangular norms or triangular conorms. When T is an upper semicontinuous triangular norm, some necessary and sufficient conditions are established in such a way that the FBAMs based on the max-T composition are globally stable, and the stable states and the equilibria of the FBAMs were studied. When T is a continuous triangular norm, it is proved that the sequence of reverberation states of the learning FBAM is nonincreasing.
Multivariate aging properties of epoch times of nonhomogeneous processes
Authors: Félix Belzunce, José A. Mercader, José M. Ruiz
Venue: Journal of Multivariate Analysis (2003)

The purpose of this paper is to give conditions on the parameters of nonhomogeneous Poisson and nonhomogeneous pure birth processes, under which the corresponding random vector of the first n epoch times has some multivariate stochastic properties. These results provide an inside to understand the effect of the time over the occurrence of events in such processes. Some applications of these results are given.
Recognizing DNA graphs is difficult
Authors: Rudi Pendavingh, Petra Schuurman, Gerhard J. Woeginger
Venue: Discrete Applied Mathematics (2003)

DNA graphs are the vertex induced subgraphs of De Bruijn graphs over a four letter alphabet. In this paper, we prove the NP-hardness of various recognition problems for subgraphs of De Bruijn graphs; in particular, the recognition of DNA graphs is shown to be NP-hard. As a consequence, two open questions from a recent paper by Biazewicz et al. (Discrete Appl. Math. 98, (1999) 1) are answered in the negative.
Enumerating extreme points in higher dimensions
Authors: Thomas Ottmann, Sven Schuierer, Subbiah Soundaralakshmi
Venue: Nordic Journal of Computing (2001)

We consider the problem of enumerating all extreme points of a given set P of n points in d dimensions. We present a simple and practical algorithm which uses O(n) space and O(nm) time, where m is the number of extreme points of P. Our algorithm is designed to work even for highly degenerate input.We also present an algorithm to compute the depth of each point of the given set of n points in d-dimensions. This algorithm has time complexity O(n2) which significantly improves the O(n3) complexity of the naive algorithm.
Checking behavioural subtypes via refinement
Authors: Heike Wehrheim
Venue: Proceedings of the IFIP TC6/WG6.1 Fifth International Conference on Formal Methods for Open Object-Based Distributed Systems V (2002)

Behavioural subtyping is concerned with the question of whether one class is behaviourally consistent with another class. The word "behaviour" in this context usually refers to the semantics of methods, typically given by pre- and postconditions. In this paper, we will use this term in a more specific way, referring to the dynamic behaviour of objects in time. Behaviour descriptions of classes give sequencing constraints on method invocations, in this paper formulated using the process algebra CSP.Behavioural subtyping can be seen as a mixture of refinement and inheritance: we expect the subtype to be substitutable for the supertype while at the same moment allowing extension of functionality. Since refinement itself does not allow extension of functionality, a subtyping definition must therefore extend standard refinement concepts to cope with additional methods in the subtype. In this paper, we show for three such subtyping relations how they can, despite these extensions, be checked via refinement. This gives us the possibility of employing standard refinement checkers for CSP (viz. the FDR modelchecker) for subtype checks.
BlueBoX: A policy-driven, host-based intrusion detection system
Authors: Suresh N. Chari, Pau-Chen Cheng
Venue: ACM Transactions on Information and System Security (TISSEC) (2003)

Detecting attacks against systems has, in practice, largely been delegated to sensors, such as network intrustion detection systems. However, due to the inherent limitations of these systems and the increasing use of encryption in communication, intrusion detection and prevention have once again moved back to the host systems themselves. In this paper, we describe our experiences with building BlueBox, a host-based intrusion detection system. Our approach, based on the technique of system call introspection, can be viewed as creating an infrastructure for defining and enforcing very fine-grained process capabilities in the kernel. These capabilities are specified as a set of rules (policies) for regulating access to system resources on a per executable basis. The language for expressing the rules is intuitive and sufficiently expressive to effectively capture security boundaries.We have prototyped our approach on Linux operating system kernel and have built rule templates for popular daemons such as Apache and wu-ftpd. Our design has been validated by testing against a comprehensive database of known attacks. Our system has been designed to minimize the kernel changes and performance impact and thus can be ported easily to new kernels. We describe the motivation and rationale behind BlueBox, its design, implementation on Linux, and how it relates to prior work on detecting and preventing intrusions on host systems.
Emotional expressiveness in visual-sonic integration: a framework for multimedia design
Authors: Kritsachai Somsaman
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

A review of studies from psychology, music and cognitive science suggests that emotional expressiveness from the perception of visual and sonic information is comprised of two dimensions - valence and activation. These two dimensions can be used as a framework to guide design for emotional expressiveness in multimedia. This paper discusses the formation of this theoretically derived framework.
Using Cyclic Planning to Manage Capacity at ALCOA
Authors: Edie Schmidt, Maqbool Dada, James Ward, Duane Adams
Venue: Interfaces (2001)

ALCOA makes aluminum-tubing products to order. The product lines' success caused a backlog of customer orders and long customer lead times. This problem was exacerbated by frequent machine breakdowns at a bottleneck operation. ALCOA implemented cyclic planning to improve capacity management. The results were immediate and dramatic. Over eight months, output increased by over 20 percent, almost eliminating the backlog of customer orders. The cyclic-planning implementation resulted in additional benefits throughout the organization, including improved workforce planning and better machine maintenance scheduling.
Adaptive homing: robotic exploration tours
Authors: Verena Vanessa Hafner
Venue: Adaptive Behavior (2001)

In this article, a minimalistic model for learning and adaptation of visual homing is presented. Normalized Hebbian learning is used during exploration tours of a mobile robot to learn visual homing and to adapt to the sensory modalities. The sensors of the mobile robot (omnidirectional camera, magnetic compass) have been chosen in a way that their data most closely resemble the sensory data at the disposal of insects such as the desert ant Cataglyphis (almost omnidirectional vision, polarized light compass), which is an amazing navigator despite its tiny brain. The learned homing mechanism turned out to be closely related to Lambrinos and colleagues' average landmark vector (ALV) model and is widely independent of any special features of the environment. In contrast to the ALV model or other models of visual homing, feature extraction or landmark segmentation is not necessary. Mobile robot experiments have been performed in an unmodified office environment to test the feasibility of learning of visual homing.
A global optimum search algorithm for the joint replenishment problem under power-of-two policy
Authors: Fang-Chuan Lee, Ming-Jong Yao
Venue: Computers and Operations Research (2003)

In this study, we perform theoretical analysis and derive a global optimum search algorithm for the joint replenishment problem (JRP) under power-of-two (PoT) policy. The JRP models concern how to determine lot sizes and to schedule replenishment times for products so as to minimize the total costs per unit time. PoT policy requires replenishment frequency of each product, denoted by ki, to be a PoT integer, i.e., ki = 2p where p=0, 1, 2,.... By utilizing a 10-product example, we graphically present the curve of the optimal total cost with respect to the values of basic period. Under PoT policy, we prove that the optimality structure of the JRP is piece-wise convex. By making use of the junction points in the optimality structure, we derive an effective search algorithm to secure a global optimal solution for the JRP under PoT policy. Evidently, we provide a numerical example to demonstrate the efficiency of the proposed algorithm.
Model Checking UML Statechart Diagrams Using JACK
Authors: Stefania Gnesi, Diego Latella, Mieke Massink
Venue: The 4th IEEE International Symposium on High-Assurance Systems Engineering (1999)

Statechart Diagrams provide a graphical notation for describing dynamic aspects of system behaviour within the Unified Modeling Language (UML). In this paper we present a branching time model-checking approach to the automatic verification of formal correctness of UML Statechart Diagrams specifications. We use a formal operational semantics for building a labeled transition system (automaton) which is then used as a model to be checked against correctness requirements expressed in the action based temporal logics ACTL. Our reference verification environment is JACK, where automata are represented in a standard format, which facilitates the use of different tools for automatic verification.
Algorithmic transformation techniques for efficient exploration of alternative application instances
Authors: Todor Stefanov, Bart Kienhuis, Ed Deprettere
Venue: Proceedings of the tenth international symposium on Hardware/software codesign (2002)

Following the Y-chart paradigm for designing a system, an application and an architecture are modeled separately and mapped onto each other in an explicit design step. Next, a performance analysis for alternative application instances, architecture instances and mappings has to be done, thereby exploring the design space of the target system. Deriving alternative application instances is not trivially done. Nevertheless, many instances of a single application exist that are worth to be derived for exploration. In this paper, we present algorithmic transformation techniques for systematic and fast generation of alternative application instances that express task-level concurrency hidden in an application in some degree of explicitness. These techniques help a system designer to speedup significantly the design space exploration process.
Folding of logic functions and its application to look up table compaction
Authors: Shinji Kimura, Takashi Horiyama, Masaki Nakanishi, Hirotsugu Kajihara
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

The paper describes the folding method of logic functions to reduce the size of memories for keeping the functions. The folding is based on the relation of fractions of logic functions. We show that the fractions of the full adder function have the bit-wise NOT relation and the bit-wise OR relation, and that the memory size becomes half (8-bit). We propose a new 3--1 LUT with the folding mechanisms whcih can implement a full adder with one LUT. A fast carry propagation line is introduced for a multi-bit addition. The folding and fast carry propagation mechanisms are shown to be useful to implement other multi-bit operations and general 4 input functions without extra hardware resources. The paper shows the reduction of the area consumption when using our LUTs compared to the case using 4--1 LUTs on several benchmark circuits.
On the asymptotics of Fekete-type points for univariate radial basis interpolation
Authors: L. P. Bos, U. Maier
Venue: Journal of Approximation Theory (2002)

Suppose that K ⊂ Rd is compact and that we are given a function f ∈ C(K) together with distinct points xi ∈ K, 1 ≤i≤n. Radial basis interpolation consists of choosing a fixed (basis) function g : R+ → R and looking for a linear combination of the translates g(|x- xj|) which interpolates f at the given points. Specifically, we look for coefficients cj ∈ R such that F(x) = Σj=1n cjg(|x - xj|) has the property that F(xi)=f(xi), 1 ≤ i ≤ n. The Fekete-type points of this process are those for which the associated interpolation matrix [g(|xi - xj|)]1≤i,j≤n has determinant as large as possible (in absolute value). In this work, we show that, in the univariate case, for a broad class of functions g, among all point sequences which are (strongly) asymptotically distributed according to a weight function, the equally spaced points give the asymptotically largest determinant. This gives strong evidence that the Fekete points themselves are indeed asymptotically equally spaced.
Assessing the value of a cursor pointing device for remote collaboration on physical tasks
Authors: Susan R. Fussell, Leslie D. Setlock, Elizabeth M. Parker, Jie Yang
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This study assessed the value of a cursor pointer that allows remote collaborators to point to locations in a partner's workspace via a shared video feed. We compared performance with the cursor pointer with that in video-only and side-by-side conditions. Results indicated that participants found the cursor pointer of value for referring to objects and locations in the work environment, but that the pointer did not improve performance time over video-only. We conclude that cursor pointing is valuable for collaboration on physical tasks, but that additional gestural support will be required to make performance using video systems as good as performance working side-by-side.
Measuring the Performance of Neonatal Care Units in Scotland
Authors: Kamal Field, Ali Emrouznejad
Venue: Journal of Medical Systems (2003)

Policy makers continue to debate whether or not to increase the share of health care expenditures in United Kingdom. On the other hand, the pressure of operating within tight budgets and the advances in technology are forcing more locally based hospitals to close. One that could be used by policy makers as a benchmark is the measure of relative performance of hospitals. Many researchers have examined the source of inefficiency in health sectors (see, for example, Harris et al. Oper. Res. Soc. 57: 801&ndash;811, 2000, Ozcan et al., Med. Case 30:781&ndash;784, 1992&semi; Ozcan et al., J. Med. Syst. 20(3)141&ndash;150, 1996&semi; and Grosskopf and Valdmanis, J. Health. Econ. 6:89&ndash;107, 1987 but there is no evidence of measuring performance of neonatal care units of Scottish hospitals in the DEA literature. The purpose of this paper is to measure both technical and scale efficiency using data envelopment analysis in a selection of 22 neonatal care units in Scotland. The analysis suggests that major inefficiency likely exists in health care production in United Kingdom. There is potential for improving productivity by 20%.