varunr14/newsummary huggingface dataset:
Lateral transshipments are an effective strategy to pool inventories . We present a Semi Markov decision problem formulation for proactive and reactive transshipments in a multi location continuous review distribution inventory system with Poisson demand and one for one replenishment policy . For a two location model we state the monotonicity of an optimal policy . In a numerical study we compare the benefits of proactive and different reactive transshipment rules . The benefits of proactive transshipments are the largest for networks with intermediate opportunities of demand pooling and the difference between alternative reactive transshipment rules is negligible . 


Summary: Semi Markov decision problem formulation. Benefits of proactive over different reactive transshipment rules. Networks with intermediate opportunities of demand pooling. The difference between reactive transshipment rules is negligible.
Topic time reflects the temporal feature of topics in Web news pages which can be used to establish and analyze topic models for many time sensitive text mining tasks . However there are two critical challenges in discovering topic time from Web news pages . The first issue is how to normalize different kinds of temporal expressions within a Web news page e.g . explicit and implicit temporal expressions into a unified representation framework . The second issue is how to determine the right topic time for topics in Web news . Aiming at solving these two problems we propose a systematic framework for discovering topic time from Web news . In particular for the first issue we propose a new approach that can effectively determine the appropriate referential time for implicit temporal expressions and further present an effective defuzzification algorithm to find the right explanation for a fuzzy temporal expression . For the second issue we propose a relation model to describe the relationship between news topics and topic time . Based on this model we design a new algorithm to extract topic time from Web news . We build a prototype system called Topic Time Parser and conduct extensive experiments to measure the effectiveness of our proposal . The results suggest that our proposal is effective in both temporal expression normalization and topic time extraction . 


Summary: We present a systematic framework for discovering topic time from Web news. We propose a new approach to determine the referential time for implicit temporal expressions. We devise a relation model between news topics and topic time for topic time extraction. We build a prototype system and conduct comparative experiments on real datasets.
Interactive approaches employing cone contraction for multi criteria mixed integer optimization are introduced . In each iteration the decision maker is asked to give a reference point . The subsequent Pareto optimal point is the reference point projected on the set of admissible objective vectors using a suitable scalarizing function . Thereby the procedures solve a sequence of optimization problems with integer variables . In such a process the DM provides additional preference information via pair wise comparisons of Pareto optimal points identified . Using such preference information and assuming a quasiconcave and non decreasing value function of the DM we restrict the set of admissible objective vectors by excluding subsets which can not improve over the solutions already found . The procedures terminate if all Pareto optimal solutions have been either generated or excluded . In this case the best Pareto point found is an optimal solution . Such convergence is expected in the special case of pure integer optimization indeed numerical simulation tests with multi criteria facility location models and knapsack problems indicate reasonably fast convergence in particular under a linear value function . We also propose a procedure to test whether or not a solution is a supported Pareto point . 


Summary: An interactive approach for a mixed integer multi criteria optimization is introduced. The DM makes pairwise comparisons of identified Pareto optimal points and gives reference points. Assuming a quasi concave value function pairwise comparisons are used to contract the cone of admissible objective vectors. Numerical simulation tests indicate reasonably fast convergence. Convergence is guaranteed for the pure integer case.
One of the problems of opinion mining is the domain adaptation of the sentiment classifiers . There are several approaches to tackling this problem . One of these is the integration of a list of opinion bearing words for the specific domain . This paper presents the generation of several resources for domain adaptation to polarity detection . On the other hand the lack of resources in languages different from English has orientated our work towards developing sentiment lexicons for polarity classifiers in Spanish . The results show the validity of the new sentiment lexicons which can be used as part of a polarity classifier . 


Summary: A lexicon based domain adaptation method is proposed. Several domain polar lexicons were compiled following a corpus based approach. The new resources are assessed over a Spanish corpus. The promising results encourage us to follow improving this domain adaptation method.
In this article we present a new exact algorithm for solving the simple assembly line balancing problem given a determined cycle time . The algorithm is a station oriented bidirectional branch and bound procedure based on a new enumeration strategy that explores the feasible solutions tree in a non decreasing idle time order . The procedure uses several well known lower bounds dominance rules and a new logical test based on the assimilation of the feasibility problem for a given cycle time and number of stations to a maximum flow problem . The algorithm has been tested with a series of computational experiments on a well known set of problem instances . The tests show that the proposed algorithm outperforms the best existing exact algorithm for solving SALBP 1 verifying optimality for 264 of the 269 benchmark instances . 


Summary: A new branch and bound is proposed for the simple assembly line balancing problem. A novel flow based logical test and a strengthened dominance rule are put forward. The results from the proposed algorithm outperform those provided by the previous procedures found in the literature.
We consider single item and inventory systems with integer valued demand processes . While most of the inventory literature studies continuous approximations of these models and establishes joint convexity properties of the policy parameters in the continuous space we show that these properties no longer hold in the discrete space in the sense of linear interpolation extension and L convexity . This nonconvexity can lead to failure of optimization techniques based on local optimality to obtain the optimal inventory policies . It can also make certain comparative properties established previously using continuous variables invalid . We revise these properties in the discrete space . 


Summary: First paper to focus on discrete r q and s T inventory systems. Some well known properties of the continuous systems no longer hold. Show exactly where joint convexity breaks down and establish other useful properties. Revise comparative properties of the continuous model for the discrete model.
The purpose of this article is to validate through two empirical studies a new method for automatic evaluation of written texts called Inbuilt Rubric based on the Latent Semantic Analysis technique which constitutes an innovative and distinct turn with respect to LSA application so far . In the first empirical study evidence of the validity of the method to identify and evaluate the conceptual axes of a text in a sample of 78 summaries by secondary school students is sought . Results show that the proposed method has a significantly higher degree of reliability than classic LSA methods of text evaluation and displays very high sensitivity to identify which conceptual axes are included or not in each summary . A second study evaluates the method s capacity to interact and provide feedback about quality in a real online system on a sample of 924 discursive texts written by university students . Results show that students improved the quality of their written texts using this system and also rated the experience very highly . The final conclusion is that this new method opens a very interesting way regarding the role of automatic assessors in the identification of presence absence and quality of elaboration of relevant conceptual information in texts written by students with lower time costs than the usual LSA based methods . 


Summary: We model how to implement a rubric in latent semantic analysis. The proposed method change abstract dimensions into meaningful dimensions. The method allows to detect easily written contents. Inbuilt rubric method has been used to give feedback to 924 university students.
Trade credit arises when a buyer delays payment for purchased goods or services . Its nature has predominantly been an area of inquiry for researchers from the disciplines of finance marketing and economics but it has received relatively little attention in other domains . In our article we provide an integrative review of the existing literature and discuss conflicting study outcomes . We organize the relevant literature into seven areas of inquiry and analyze four in detail trade credit motives order quantity decisions credit term decisions and settlement period decisions . Additionally we derive a detailed agenda for future research in these areas . 


Summary: We provide an integrative review of the existing literature of trade credit in the interface of operations and finance. We analyze in detail four literature areas trade credit motives order quantity decisions credit term decisions and settlement period decisions. The main findings of the literature review is that trade credit increases the economic order quantity and could serve as a buyer supplier coordination mechanism. We derive a detailed agenda for future research around two core themes opportunities arising from inside operations management and opportunities arising from outside operations management.
Social media represents an emerging challenging sector where the natural language expressions of people can be easily reported through blogs and short text messages . This is rapidly creating unique contents of massive dimensions that need to be efficiently and effectively analyzed to create actionable knowledge for decision making processes . A key information that can be grasped from social environments relates to the polarity of text messages . To better capture the sentiment orientation of the messages several valuable expressive forms could be taken into account . In this paper three expressive signals typically used in microblogs have been explored adjectives emoticon emphatic and onomatopoeic expressions and expressive lengthening . Once a text message has been normalized to better conform social media posts to a canonical language the considered expressive signals have been used to enrich the feature space and train several baseline and ensemble classifiers aimed at polarity classification . The experimental results show that adjectives are more discriminative and impacting than the other considered expressive signals . 


Summary: To capture the sentiment of messages several expressive forms are investigated. Expressive signals enrich the feature space of baseline and ensemble classifiers. Only adjectives play a fundamental role as expressive signal. Pragmatic particles and expressive lengthening could lead to the de finition of erratic polarity classifiers.
We develop a dynamic continuous time theory of the competitive firm under multiple correlated uncertainties . In doing so we completely generalize and extend the previous comparative statics results . Particularly we relax the assumption of the statistical independence between the risks and the restrictions on the coefficient of absolute relative risk aversion . Furthermore we generally show the impact of one risk on the aversion to another . Moreover we show the role of the factor of correlation between risks on the decisions of the firm . 


Summary: A dynamic model of the firm under multiple correlated uncertainties. Completely generalize the previous static results. The impact of one risk on the aversion to another.
Autonomous word of mouth as a channel of social influence that is out of firms direct control has acquired particular importance with the development of the Internet . Depending on whether a given product or service is a good or a bad deal this can significantly contribute to commercial success or failure . Yet the existing dynamic models of sales in marketing still assume that the influence of word of mouth on sales is at best advertising dependent . This omission can produce ineffective management and therefore misleading marketing policies . This paper seeks to bridge the gap by introducing a contagion sales model of a monopolist firm s product where sales are affected by advertising dependent as well as autonomous word of mouth . We assume that the firm s attraction rate of new customers is determined by the degree at which the current sales price is advantageous or not compared with the current customers reservation price . A primary goal of the paper is to determine the optimal sales price and advertising effort . We show that despite costly price adjustments the interactions between sales price advertising dependent and autonomous word of mouth can result in complex dynamic pricing policies involving history dependence or limit cycling consisting of alternating attraction of new customers and attrition of current customers . 


Summary: We study dynamic pricing and advertising policies in a sales model for a monopolist firm. Both autonomous and advertising dependent word of mouth are considered. Optimal limit cycles alternating building and leveraging of the price advantage are found. Multiple equilibria separated by Skiba curves are numerically ascertained.
The existence of positive and negative externalities ought to be considered in a productivity analysis in order to obtain unbiased measures of efficiency . In this research we present an additive style data envelopment analysis model that considers the production of both negative and positive externalities and permits a limited increase in input utilisation where relevant . The directional economic environmental distance function is a unified approach based on a linear program that evaluates the relative inefficiency of the units under examination with respect to a unique reference technology . We discuss the impact of disposability assumptions in depth and demonstrate how different versions of the DEED model improve on models presented in the literature to date . 


Summary: Positive and negative externalities ought to be modelled to obtain unbiased measures of productivity. We develop an additive style data envelopment analysis model that accounts for both externalities. We model limited increases in input utilisation in order to further reduce negative externalities. The directional economic environmental distance DEED function is a unified approach. DEED draws from a unique reference technology enabling reasonable productivity measure comparisons.
Faced with a short turn around request to characterise several hand held mine detection systems the authors developed and applied an analytical methodology that was sufficiently robust and pragmatic to satisfy the needs of the various military stakeholders involved yet it was appropriately rigorous and transparent to bear external scrutiny . The methodology can be applied in situations where data collection and analysis must be done quickly while preserving scientific veracity . For mine detection systems considerable uncertainties existed that needed to be characterised including application location operational situation and involvement of human operators . Constraints on the time and expertise available implied there would be difficulties ensuring a sufficient number of trials could be conducted to levels of statistical confidence that would assure appropriate credibility across all of the parameters . This problem was effectively rectified through experimental design and by heavily involving the sponsor stakeholders and subject matter experts throughout the study thus boosting the credibility and acceptance of its results . The process followed involved liaison with the sponsor identification of critical issues measurements in field environments reporting mechanisms and discussion on implementation and further development . The critical focus was operational capability rather than specific equipment characteristics . A robust data presentation technique was developed to deal with the complexities associated with different needs of multiple stakeholders . This technique enabled the results to be reviewed from different stakeholders perspectives the formation of a common understanding and the results to be reusable in future analyses . 


Summary: We develop and apply a methodology to characterise hand held detection systems. Methodology which incorporates field trials and workshops allows scrutiny. Robust data presentation technique was developed to facilitate common understanding. Methodology and presentation satisfies the needs of multiple stakeholder groups. Can be applied to future detectors allowing direct comparisons to be made.
We analyze a time fenced planning system where both expediting and canceling are allowed inside the time fence but only with a penalty . Previous research has allowed only for the case of expediting inside the time fence and has overlooked the opportunity for additional improvement by also allowing for cancelations . Some researchers also have found that for traditional time fenced models the choice of the more complex stochastic linear programming approach versus the simpler deterministic approach is not justified . We formulate both the deterministic and stochastic problems as dynamic programs and develop analytic bounds that limit the search space of the stochastic approach . We run extensive simulations and numerical experiments to understand better the benefit of adding cancelation and to compare the performance of the stochastic model with the more common deterministic model when they are employed as heuristics in a rolling horizon setting . Across all experiments we find that allowing expediting lowered costs by 11.3 using the deterministic approach but costs were reduced by 27.8 if both expediting and canceling are allowed . We find that the benefit of using the stochastic model versus the deterministic model varies widely across demand distributions and levels of recourse the ratio of stochastic average costs to deterministic average costs ranged from 43.3 to 78.5 . 


Summary: We analyze a time fenced planning system with penalized expediting and canceling. We formulate deterministic and stochastic dynamic programs and develop bounds. Allowing both expediting and canceling lowered costs 28 versus 11 for expediting only.
In this paper the resource constrained project scheduling problem with general temporal constraints is extended by the concept of break calendars in order to incorporate the possible absence of renewable resources . Three binary linear model formulations are presented that use either start based or changeover based or execution based binary decision variables . In addition a priority rule method as well as three different versions of a scatter search procedure are proposed in order to solve the problem heuristically . All exact and heuristic solution procedures use a new and powerful time planning method which identifies all time and calendar feasible start times for activities as well as all corresponding absolute time lags between activities . In a comprehensive performance analysis small and medium scale instances are solved with CPLEX 12.6 . Furthermore large scale instances of the problem are tackled with scatter search where the results of the three versions are compared to each other and to the priority rule method . 


Summary: We consider the RCPSP with general temporal constraints and break calendars. A new and powerful time planning method is proposed. Three binary linear model formulations are presented. A priority rule method and three different versions of a scatter search procedure are developed. We provide a test set and perform an extensive computational study.
This note takes up a shortcoming of Coelli et al . s popular environmental efficiency measure and its extension to economic environmental trade off analysis namely that they do not reward emission reductions by pollution control . A new environmental efficiency measure that overcomes this issue and similar to Coelli et al . s efficiency measure is in line with the materials balance principle is proposed and further decomposed into technical environmental efficiency and material and nonmaterial allocative environmental efficiencies . The new efficiency measure collapses into Coelli et al . s efficiency measure if none of the considered Decision Making Units control pollutants . A numerical example using Data Envelopment Analysis is provided to further explore the properties of the new efficiency measure . 


Summary: Coelli et al. s 2007 environmental efficiency measure does not reward pollution control. Neglecting efforts to control pollutants may lead to biased environmental efficiency scores. A new environmental efficiency measure that rewards pollution control efforts is proposed. A numerical example using Data Envelopment Analysis is provided.
We introduce and solve the Vehicle Routing Problem with Simultaneous Pick ups and Deliveries and Two Dimensional Loading Constraints . The 2L SPD model covers cases where customers raise delivery and pick up requests for transporting non stackable rectangular items . 2L SPD belongs to the class of composite routing packing optimization problems . However it is the first such problem to consider bi directional material flows dictated in practice by reverse logistics policies . The aspect of simultaneously satisfying deliveries and pick ups has a major impact on the underlying loading constraints feasible loading patterns must be identified for every arc traveled in the routing plan . This implies that 2L SPD generalizes previous routing problem variants with two dimensional loading constraints which call for one feasible loading per route . From a managerial perspective the simultaneous service of deliveries and pick ups may bring substantial cost savings but the generalized loading constraints are very hard to tackle in reasonable computational times . To this end we propose an optimization framework which employs memorization techniques designed for the 2L SPD model to accelerate the solution methodology . To assess the performance of our routing and packing algorithmic components we have solved the Vehicle Routing Problem with Simultaneous Pick ups and Deliveries and the Vehicle Routing Problem with Two Dimensional Constraints . Computational results are also reported on newly constructed 2L SPD benchmark problems . Apart from the basic 2L SPD version we introduce the 2L SPD with LIFO constraints which prohibit item rearrangements along the routes . Computational experiments are conducted to understand the impact of the LIFO constraints on the routing plans obtained . 


Summary: We introduce a problem generalizing previous VRPs with 2 D loading constraints. Memorization strategies are employed for keeping the CPU times in acceptable levels. Extensive computational results on well known benchmark instances are reported. The proposed model promotes high loading space utilization throughout the routes. Item rearrangements along vehicle routes bring significant routing cost savings.