Choice Constraints Research Articles

Semantic Constraint and QoS-Aware Large-Scale Web Service Composition

Service-oriented architecture facilitates the running time of interactions by using business integration on the networks. Currently, web services are considered as the best option to provide Internet services. Due to an increasing number of Web users and the complexity of users’ queries, simple and atomic services are not able to meet the needs of users; and to provide complex services, it requires service composition. Web service composition as an effective approach to the integration of business institutions’ plans has taken significant acceleration. Nowadays, web services are created and updated in a moment. Therefore, in the real world, there are many services which may not have composability according to the conditions and constraints of the user's preferred choice. In the proposed method for automatic service composition, the main requirements of users including available inputs, expected outputs, quality of service, and the priority are initially and explicitly specified by the user and service composition is done with this information. In the proposed approach, due to a large number of services with the same functionality, at first, the candidate services are reduced by the quality of service-based Skyline method, and moreover, by using an algorithm based on graph search, all possible solutions will be produced. Finally, the user’s semantic constraints are applied on service composition, and the best composition is offered according to user’s requests. The result of this study shows that the proposed method is more scalable and efficient, and it offers a better solution by considering the user’s semantic constraints.

A universal map of three-dominant-pole assignment for PID controller tuning

ABSTRACT A novel dimensionless parameterisation of the three-pole assignment for control plants with delay is presented. A second-order model with input delay is chosen as an approximation of the plant properties. The prescribed trio of poles is considered in form of one pair of complex conjugates and a real pole and it is shown that this option is not a matter of choice but necessary constraint for control design with delay in the loop. The prescribed poles are determined by the damping and root ratios with a natural frequency derived from the ultimate frequency of the plant. The three-pole assignments are determined by two similarity numbers considered as coordinates of the map. The limitation of admissible damping ratio due to the dominance condition is one of the original results presented in the paper. Furthermore, the influence of the root ratio is evaluated and final design recommendations are presented.

Attainable Volumetric Targets for Adsorption-Based Hydrogen Storage in Porous Crystals: Molecular Simulation and Machine Learning

Hydrogen fuel is attractive to power vehicles without emitting carbon, but onboard storage of sufficiently densified hydrogen at moderate pressure remains a significant challenge. Adsorption-based storage in porous crystals such as metal–organic frameworks and covalent organic frameworks is attractive to reduce the storage pressure. It is, however, unclear to what extent volumetric storage targets can be met under constraints of adsorbent design and choice of operating conditions. To help elucidate attainable values for volumetric storage metrics upon the potential introduction of strong hydrogen-binding sites, we “computationally synthesized” a library of porous crystals and performed 18 000+ grand canonical Monte Carlo simulations to calculate hydrogen loadings at multiple T, P conditions. The studied frameworks are based on 17 pore topologies and feature alchemical catecholate sites: sites whose interaction with hydrogen was artificially and systematically modified within the range of density functiona...

일반상한 및 확장된 다중선택 제약을 갖는 연속 예산배정문제

일반상한 및 확장된 다중선택 제약을 갖는 연속 예산배정문제

Living arrangements of the elderly: A new perspective from choice constraints in China

As the foundation of elderly care, living arrangements are closely connected with the physical and psychological well-being of the elderly and the social resources allocation. The objective of this study is to understand the constraints between the preferred and actual choices of elderly living arrangements in China. We first establish a standardized theoretical model and derive two hypotheses on choice constraints. Based on the CHARLS database, we empirically test the theoretical hypotheses based on multiple-step empirical tests. Our findings are as follows. 1) The correlation between elderly income and the likelihood of living with their children is nonlinear: when the elderly prefers to live apart, their higher absolute income provides a greater likelihood that they can do so, and when they prefer to live with their children, the relative income of the elderly and their children are important in the likelihood of living together. 2) The poorer the health status of the elderly, the greater likelihood that they live with their children, particularly if they have daughters. The results are robust after controlling for the potential endogeneity issue, the passive choice situation, and volatility in preference.

A Genetic Algorithm Based Hybrid Approach for Reliability-Redundancy Optimization Problem of a Series System with Multiple-Choice

The goal of this paper is to introduce an application of hybrid algorithm in reliability optimization problems for a series system with parallel redundancy and multiple choice constraints to maximize the system reliability subject to system budget and also to minimize the system cost subject to minimum level of system reliability. Both the problems are solved by using penalty function technique for dealing with the constraints and hybrid algorithm. In this algorithm, the well-known real coded Genetic Algorithm is combined with Self-Organizing Migrating Algorithm. As special cases, both the problems are formulated and solved considering single component without redundancy. Finally, the proposed approach is illustrated by some numerical examples and the computational results are discussed.

Multi-objective design optimisation of repairable k-out-of-n subsystems in series with redundant dependency

Several researches have been investigated on Multi-Objective Redundancy Allocation Problems (MORAPs), but none of them have considered the redundant dependency at the design stage. This latter which is a special kind of failure dependency can affect significantly the system performance. Due to this fact, this paper deals with the multi-objective system design optimisation with dependent components by focusing on two objectives: maximisation of system availability and minimisation of system cost with components choice and weight constraints. A system consisting of many k-out-of-n repairable subsystems connected in series is considered. The components of a subsystem are supposed to be identical and may be dependent. They are selected from a set of available component types. In addition to the redundancy level and the number of repair teams allocated to each subsystem, the choice of components type and the dependency level are also considered as decision variables. Since the described problem is NP hard, we propose three multi-objective meta-heuristic algorithms based on Non-dominated Sorting Genetic Algorithm (NSGA II) and Strength Pareto Evolutionary Algorithm (SPEA II) with different constraints handling. An exact method is also applied. To analyse their performances, numerical applications are provided and comparisons based on different well-known metrics are presented.

Using multidimensional methods to understand the development, interpretation and enactment of quality assurance policy within the educational development community

ABSTRACTPolicy texts are representations of practice that both reflect and shape the world around them. There is, however, little higher education research that critically analyses the impact of higher education policy on educational developers and educational development practice. Extending methods from critical discourse analysis by combining textual analysis of a policy text with in-depth interviews with policy-makers and policy users, this article seeks to better understand the process of production, interpretation and implementation of policy. The article focuses on a leading national UK quality assurance policy in relation to the educational development community in order to uncover how policy is played out in practice. The findings paint a picture of a text that presents a version of higher education that is portrayed linguistically as universally accepted. Yet, the methodological approach enables the uncovering of the complexities of the policy process that go beyond the text’s words by highlighting the debates that shaped its development and the interpretations of its textual form that subsequently shape its enactment. Looking specifically at the constraints of policy boundaries, word choice and calls to educational development action (or inaction), the policy text is analysed in light of educational developers’ contexts and institutional positioning, surfaced through the research process itself. The article concludes by arguing that the combination of data collection and analysis methods used provide greater insights into how policy is played out in practice than the employment of any one of these methods individually could have achieved.

Making Poor Choices? Demand Rationalities and School Choice in a Chilean Local Education Market

ABSTRACTAlthough the literature on school choice rationalities is extensive, different authors interpret the processes of school choice for poor families in different ways. Positions vary between those that consider that poor families have the same capacity to choose as middle class families and those that value structural factors as constraints for choice. The objective of this article is to identify different school choice rationalities of low income families in the context of a highly marketized education system such as Chile. Beyond the restrictions of a different nature that poor families face, this social group mostly expresses high levels of reflexivity and complex sets of preferences when it comes to choosing schools for their children. This article tries to overcome the dualistic division that prevails in school choice literature between choice as an outcome of utility maximization for all, and choice as a denial for deprived groups.

How Property Markets Determine Welfare Outcomes: An Equilibrium Sorting Model Analysis of Local Environmental Interventions

This paper examines the pivotal role played by property markets in determining the magnitude and distribution of welfare changes resulting from localised environmental change. We address that issue using an equilibrium sorting model (ESM) calibrated, by way of example, to the circumstances of a road infrastructure project in the English town of Polegate. Previous ESM research has tended to assume that all households rent property from a fixed property stock. The narrative that arises from those models concerns environmental gentrification, wherein access to environmentally improved locations is appropriated by the relatively wealthy through their ability to out-compete the less wealthy in the rental property market. Our research shows that to be only part of a much more complex story. We develop a model that extends the sophistication with which ESMs replicate property market dynamics, allowing for households to choose whether to rent or purchase their home and introducing greater realism into housing supply responses to changing market conditions. Our research shows that property markets redistribute welfare gains across the population in complex ways in which tenure choice and housing supply constraints play central roles.

Pobreza infantil no Brasil: aplicação da metodologia Alkire-Foster de mensuração de pobreza multidimensional

O presente estudo propõe exercício de medição inédita da incidência e intensidade da pobreza infantil no Brasil a partir dos dados da PNDS 2006, utilizando a metodologia elaborada por Alkire & Foster (2009, 2011) para mensuração de pobreza multidimensional e sua especificação para pobreza infantil proposta por Alkire & Roche (2012). Conclui-se que, apesar da dificuldade de obtenção de dados primários e da arbitrariedade intrínseca à escolha de dimensões em medidas multidimensionais, os benefícios da metodologia adotada superam essas adversidades em função de sua formulação robusta e intuitiva. Medidas de incidência e intensidade da pobreza são apresentadas para os estratos rural e urbano das cinco macrorregiões do Brasil, esboçando os diferentes perfis de pobreza no Sudeste urbano e Nordeste rural

Free to Choose? Reform, Choice, and Consideration Sets in the English National Health Service.

Choice in public services is controversial. We exploit a reform in the English National Health Service to assess the effect of removing constraints on patient choice. We estimate a demand model that explicitly captures the removal of the choice constraints imposed on patients. We find that, post-removal, patients became more responsive to clinical quality. This led to a modest reduction in mortality and a substantial increase in patient welfare. The elasticity of demand faced by hospitals increased substantially post- reform and we find evidence that hospitals responded to the enhanced incentives by improving quality. This suggests greater choice can raise quality.

Power, Fairness and Constrained Choice in Agricultural Markets: A Synthesizing Framework

The (un)fairness of agricultural markets is frequently invoked, especially by farmers. But fairness is difficult to define and measure. In this paper we link fairness and power with the concept of constrained choice to develop a framework for assessing fairness in agricultural markets. We use network exchange theory to define power from the dependencies that exist in agricultural networks. The structure of agricultural networks and the options that agricultural producers have to participate in agricultural networks affect the degree to which they are dependent on others within the network. Dependency, in turn, affects the choices that agricultural producers have. We consider both the number and nature of these choices. We argue that constraining or limiting choices—both in number and type—violates principles of justice. Importantly, network exchange theory provides a method for assessing constraints in choices and, hence, the fairness of agricultural markets. Such an assessment could potentially lead to new policies that safeguard the liberties of marketplace participants. We present a brief case to illustrate how this framework can inform on the fairness of agricultural markets and conclude with considerations of what this means for policy, particularly in the arena of anti-trust.

The Mobile Territorial Lab: a multilayered and dynamic view on parents’ daily lives

The exploration of people’s everyday life has long been of interest to social scientists. Recent years have witnessed a growing interest in analyzing human behavioral data generated by technology (e.g. mobile phones). To date, a few large-scale studies have been designed to measure human behaviors and interactions using multiple sources of data. A common characteristic of these studies is the population under investigation: students having similar daily routines and needs. This choice constraints the range of behaviors, of places and the generalization of the results. In order to widen this line of studies, we focus on a different target group: parents with young children aged 0 through 10 years. Children influence multiple aspects of their parents’ lives, from the satisfaction of basic human needs and the fulfillment of social roles to their financial status and sleep quality. In this paper, we describe the Mobile Territorial Lab (MTL) project, a longitudinal living lab which has been sensing by means of technology (mobile phones) the lives of more than 100 parents in different areas of the Trentino region in Northern Italy. We present the preliminary results after two years of experimentation of, to the best of our knowledge, the most complete picture of parents’ daily lives. Through the collection and analysis of the collected data, we created a multi-layered view of the participants’ lives, tracking social interactions, mobility routines, spending patterns, and personality characteristics. Overall, our results prove the relevance of living lab approaches to measure human behaviors and interactions, which can pave the way to new studies exploiting a richer number of behavioral indicators. Moreover, we believe that the proposed methodology and the collected data could be very valuable for researchers from different disciplines such as social psychology, sociology, computer science, economy, etc., which are interested in understanding human behaviour.

Power, Fairness and Constrained Choice in Agricultural Markets: A Synthesizing Framework

The (un)fairness of agricultural markets is frequently invoked, especially by farmers. But fairness is difficult to define and measure. In this paper we link fairness and power with the concept of constrained choice to develop a framework for assessing fairness in agricultural markets. We use network exchange theory to define power from the dependencies that exist in agricultural networks. The structure of agricultural networks and the options that agricultural producers have to participate in agricultural networks affect the degree to which they are dependent on others within the network. Dependency, in turn, affects the choices that agricultural producers have. We consider both the number and nature of these choices. We argue that constraining or limiting choices — both in number and in their type — violates principles of justice. Importantly, network exchange theory provides a method for assessing constraints in choices and, hence, the fairness of agricultural markets. Such an assessment could potentially lead to new policies that safeguard the liberties of marketplace participants. We present a brief case to illustrate how this framework can inform on the fairness of agricultural markets, and conclude with considerations of what this means for policy, particularly in the arena of anti-trust.

Maintaining Mobility in Substantial Urban Growth Futures

Integrated land use/transport models traditionally follow a simple integration concept: The land use model provides the origins and destinations of trips, and the travel demand model provides aggregate travel times between zones. High levels of congestion and the limitation of travel budgets, however, require travelers to scrutinize travel options and housing locations more carefully. In this paper, a microscopic integration of land use and transport models is proposed that – for the first time – is capable of capturing travel times and constraints at the level of the individual traveler. This level of integration allows choosing housing locations from which workplaces of all household members are accessible. In addition, discretionary travel can be limited to a household's travel budget after mandatory trips have been completed. The model is expected to represent travel and housing location choice constraints more realistically under high congestion/high cost scenarios.

Facilitating Green Building Adoption -- An Optimization Based Decision Support Tool

The US Environmental Protection Agency defines green buildings as the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle from site selection to design, construction, operation, maintenance, renovation and deconstruction.The adoption of green building norms in India is a relatively new phenomenon. The Indian Green Building Council (IGBC) has been the torch bearer for this effort since 2001. There are three major green building guidelines currently being adopted in India: (1) LEED®-New Construction LEED-NC); (2) GRIHA® by The Energy and Resources Institute (TERI) that was established voluntarily to rate buildings; and (3) LEED®-INDIA released by the Indian Green Building Council which is inspired by LEED-NC and includes alterations based on Indian construction environment.The decision to opt for green construction and the level of green aspirations is constrained by the extra cost of going green, i.e. the green premium. The level of environment friendliness, given by the rating of the building, is not arrived at in a scientific manner by considering the options and their cost implications. Risk averse owners, in spite of their desire to go green, are hindered by a lack of information on the various options and ability to decide which options to choose. This information, if made available as a decision support tool, can be valuable in bringing green buildings into the mainstream. The non availability of such a tool is a major barrier in the growth of the green building movement (USEPA report “Removing market barriers to green development”).The objective of this work is to develop an optimization based decision support tool that can be used to either arrive at the optimal green rating given the budget and choice constraints; or at the optimal green premium given the green rating aspirations. These can help a builder optimize green ratings or greening costs, as desired, or by a policy maker to come up with appropriate and effective policies. The Indian GRIHA rating guidelines are used as inputs for measuring the green rating of a building. In addition sensitivity to costs, of socially important parameters such as use of solar energy, fly-ash etc., of choices made for achieving desired green ratings are studied. This can help drive appropriate policy initiatives for adoption of such technologies.

The Impact of Traffic Information Acquisition on the Traffic Conditions of the Athens Greater Area

The main objective of this article is to gain fundamental understanding on the effect of real time information acquisition, on the traffic conditions of the Athens greater area. Activity scheduling is a dynamic process, where individuals often need to modify their schedule, as a result of new insights. Research so far hasn't analyzed the effect of traffic information acquisition, in activity scheduling, although several studies have been conducted to capture the factors that influence the rescheduling of activities. An integrated latent variable model has been estimated, that predicts the probability of rescheduling activities as a function of flexibility, mode choice constraints and travel information. The analysis of the results indicates that one of the biggest impacts of traffic information acquisition is reflected in the rescheduling of activities. Therefore, traffic information not only can significantly improve the travel experience of individuals but may directly affect the performance of the transportation system.

School choice with controlled choice constraints: Hard bounds versus soft bounds

Controlled choice over public schools attempts giving parents selection options while maintaining diversity of different student types. In practice, diversity constraints are often enforced by setting hard upper bounds and hard lower bounds for each student type. We demonstrate that, with hard bounds, there might not exist assignments that satisfy standard fairness and non-wastefulness properties; and only constrained non-wasteful assignments that are fair for same type students can be guaranteed to exist. We introduce the student exchange algorithm that finds a constrained efficient assignment among such assignments. To achieve fair (across all types) and non-wasteful assignments, we propose control constraints to be interpreted as soft bounds–flexible limits that regulate school priorities dynamically. In this setting, (i) the student-proposing deferred acceptance algorithm produces an assignment that Pareto dominates all other fair assignments while eliciting true preferences and (ii) the school-proposing deferred acceptance algorithm finds an assignment that minimizes violations of controlled choice constraints among fair assignments.

A hybrid heuristic for the multiple choice multidimensional knapsack problem

In this article, a new solution approach for the multiple choice multidimensional knapsack problem is described. The problem is a variant of the multidimensional knapsack problem where items are divided into classes, and exactly one item per class has to be chosen. Both problems are NP-hard. However, the multiple choice multidimensional knapsack problem appears to be more difficult to solve in part because of its choice constraints. Many real applications lead to very large scale multiple choice multidimensional knapsack problems that can hardly be addressed using exact algorithms. A new hybrid heuristic is proposed that embeds several new procedures for this problem. The approach is based on the resolution of linear programming relaxations of the problem and reduced problems that are obtained by fixing some variables of the problem. The solutions of these problems are used to update the global lower and upper bounds for the optimal solution value. A new strategy for defining the reduced problems is explored, together with a new family of cuts and a reformulation procedure that is used at each iteration to improve the performance of the heuristic. An extensive set of computational experiments is reported for benchmark instances from the literature and for a large set of hard instances generated randomly. The results show that the approach outperforms other state-of-the-art methods described so far, providing the best known solution for a significant number of benchmark instances.