Heuristic Works Research Articles

Routing electric vehicles with a single recharge per route

AbstractDriven by environmental considerations, regulations on vehicle emissions, and the offer of major subsidies, electric commercial vehicles (ECVs) are receiving ever stronger attention in logistics companies. Route planning for ECV fleets requires consideration of the special characteristics of ECVs, like limited driving range and the potential need to recharge en route at dedicated recharging stations. From a practical viewpoint, the number of recharge operations of each vehicle can very often be restricted to one recharge per route because (i) typical route distances in the most important application areas of ECVs, like small package shipping and food or beverage distribution, do not require more than one recharge given the current driving range of ECVs, and (ii) operations managers are very reluctant to plan vehicle routes with two or more recharges because recharging operations are perceived as unproductive idle times. We develop a simple hybrid of large neighborhood search and granular tabu search to solve the resulting electric vehicle‐routing problem with time windows and single recharge (EVRPTWS), considering the possibility of both full and partial recharge. The heuristic works on routes represented as customer sequences, and recharge operations are implicitly considered by determining the recharging position in the route, the recharging station to visit, and the amount to be recharged in optimal fashion. We discuss how our algorithm can be extended to handle nonlinear recharging times, different recharging times per station, and time‐dependent waiting times at stations. In numerical studies on EVRPTWS instances from the literature, the method provides optimal or near‐optimal solutions for instances with up to 100 customers within reasonable runtimes. Additional studies investigate the cost savings potential of partial recharges in comparison to full recharges in the presence of time‐window constraints, and examine the factors that influence this cost saving potential.

Esporas de inclusión

La educación inclusiva al ser concebida en tanto espora emerge con fines de dispersión y supervivencia en condiciones adversas. El nomadismo epistemológico de la educación inclusiva inaugura una nueva forma de concebir y practicar el trabajo heurístico. El nomadismo epistemológico de la educación inclusiva es una forma analítica dinámica, un espacio de intensos flujos, una red de apertura, creación y relación de diversas singularidades y recursos epistemológicos –principio de heterogénesis–. La naturaleza del dominio reafirma un carácter transposicional, fundamentalmente, articulado a partir de complejos y singulares flujos de movilidad y referencias cruzadas entre (inter)disciplinas, teorías, conceptos, niveles discursivos, etc. Es un territorio que se desplaza por diversos lugares produciendo-a-sí-mismo y creando sus propios efectos específicos. El trabajo describe ocho claves analíticas cruciales en la comprensión epistémica de su dominio.

An adaptive large neighbourhood search heuristic for routing and scheduling feeder vessels in multi-terminal ports

This paper proposes an Adaptive Large Neighbourhood Search heuristic for solving the Port Scheduling Problem, the problem of scheduling feeder vessels’ operations in multi-terminal ports. Each vessel has a number of operations to perform at different terminals within the port, and each terminal can only serve a single vessel at a time. The resulting problem is a general shop-like problem, with a variety of additional operational constraints. The objective is to let the vessels depart from the port as early as possible, as this allows them to sail at reduced speed to the next port, saving large amounts of fuel; as well as scheduling operations early, which leaves more slack for later and hence makes the system more robust. The developed Adaptive Large Neighbourhood Search heuristic works with the order of operations, and assigns the start times of the operations first as part of the solution evaluation. To conduct the computational experiments, a large set of benchmark test instances, denoted PortLib, was developed, and the performance of the heuristic was compared to that of a commercial solver. The results show that the heuristic in general finds better solutions, even with significantly shorter run times.

A branch‐and‐cut approach for the least cost influence problem on social networks

AbstractThis paper studies a problem in the online targeted marketing setting called the least cost influence problem (LCIP) that is known to be NP‐hard. The goal is to find the minimum total amount of inducements (individuals to target and associated tailored incentives) required to influence a given population. We develop a branch‐and‐cut approach to solve this LCIP on arbitrary graphs. We build upon Günneç et al.'s novel totally unimodular (TU) formulation for the LCIP on trees. The key observation in applying this TU formulation to arbitrary graphs is to enforce an exponential set of inequalities that ensure the influence propagation network is acyclic. We also design several enhancements to the branch‐and‐cut procedure that improve its performance. We provide a large set of computational experiments on real‐world graphs with up to 155 000 nodes and 327 000 edges that demonstrates the efficacy of the branch‐and‐cut approach. This branch‐and‐cut approach finds solutions that are on average 1.87% away from optimality based on a test‐bed of 160 real‐world graph instances. We also develop a heuristic that prioritizes nodes that receive low influence from their peers. This heuristic works particularly well on arbitrary graphs, providing solutions that are on average 1.99% away from optimality. Finally, we observe that partial incentives can result in significant cost savings, over 55% on average, compared to the setting where partial incentives are not allowed.

ГУМАНІТАРНА ДІЯЛЬНІСТЬ УКРАЇНСЬКОГО ЦЕНТРАЛЬНОГО КОМІТЕТУ В ГЕНЕРАЛЬНІЙ ГУБЕРНІЇ: ІСТОРІОГРАФІЯ

One of the unexplored and ambiguous questions about the history of Ukraine during World War ІІ is the activity of the only legal establishment of Ukrainians under the Nazi occupation regime – Ukrainian Central Committee (UCC). Scientific interest in the place of the designated organization in the context of that time social and cultural processes in Western Ukrainian lands actualizes the importance of comprehending and analyzing the accumulated historical knowledge about it. The article investigates the completeness of the study and the representation of the problem in historiography, identifying two periods of its scientific development. Attention is focused on the key trends, thematic aspects, specific results of the researches of scientists of UCC activities in the humanitarian sphere at each stage of the historiographic process. The specificity of reflection of the subject in the historical literature is traced: from factual materials of encyclopedic editions and historical-memoir publications to studies of social and political history of Ukraine, monographs, dissertations and scientific articles, educational editions that directly or indirectly cover the cultural, educational, charitable and sports activities of the UCC. Historiographic analysis convincingly proves a significant progress in the study of the problem at the latest stage through the intensification of source and archeographic studies that improve the heuristic work in the specified direction, contribute to the emergence of specialized publications of modern Ukrainian historians dedicated to finding out the place of the UCC in the revival of the national, cultural and sports life of Ukrainians in the 1940s. The features of coverage of the problem in contemporary foreign historiography, in which the leading place belongs to Polish historical thought, are revealed. Emphasis is placed on its historical and political orientation and prejudgment. It is revealed that in terms of personal dimension of the research of the work of the UCC, an important role is played by scientific understanding of the activity of his head – Volodymyr Kubiyovych.

Heuristic-Based Address Clustering in Bitcoin

With the emergence of decentralized cryptocurrencies such as Bitcoin, it has become very difficult for law enforcement to detect suspicious activities, identify users and obtain transaction records for criminals who utilize the pseudoanonymity provided by the cryptocurrency system. Address clustering aims to break such pseudoanonymity by linking addresses that are controlled by the same user based on the information available from the blockchain, such as transaction graphs. There are already two widely used heuristics for Bitcoin address clustering. One is based on the multiple input addresses of transactions. The other is based on one-time change addresses. By reconsidering the one-time change address-based heuristic from the perspective of address reuse, we propose a new heuristic that detects one-time change addresses by eliminating addresses that are reused later as non-change addresses. As a result, this heuristic works for transactions whose one-time change addresses cannot be identified by the previous two heuristics. The experimental results for different scales of Bitcoin transaction data show that the proposed heuristic has a 0.33% mean contribution to the ratio of address reduction in addition to the contribution of the multiple input addresses and one-time change address heuristics.

IMPROVING THE SHIFT-SCHEDULING PROBLEM USING NON-STATIONARY QUEUEING MODELS WITH LOCAL HEURISTIC AND GENETIC ALGORITHM

We improve the shift-scheduling process by using nonstationary queueing models to evaluate schedules and two heuristics to generate schedules. Firstly, we improved the fitness function and the initial population generation method for a benchmark genetic algorithm in the literature. We also proposed a simple local search heuristic. The improved genetic algorithm found solutions that obey the delay probability constraint more often. The proposed local search heuristic also finds feasible solutions with a much lower computational expense, especially under low arrival rates. Differently from a genetic algorithm, the local search heuristic does not rely on random choices. Furthermore, it finds one final solution from one initial solution, rather than from a population of solutions. The developed local search heuristic works with only one well-defined goal, making it simple and straightforward to implement. Nevertheless, the code for the heuristic is simple enough to accept changes and cope with multiple objectives.

ORGANIZATION DESIGN FOR ALGORITHMIC AND HEURISTIC WORK

Abstract PurposePurpose of this research is to propose the organization design parameters and coordination mechanisms that match the algorithmic and heuristic work characteristics. MethodologyMethodology used bases on the analysis of the literature. The study is conceptual in nature and draws upon other research findings. Firstly, it takes into consideration a literature review on organization architecture, design, and two types of work (algorithmic and heuristic). Then organization architecture assumptions are presented as a basis for analysis of matching organization design with algorithmic and heuristic work. Subsequently, a considered framework for analysis is Mintzberg model of organization design that is applied as a framework to be checked for fit with heuristic work characteristics. FindingsResearch leads to conclusion that out of five organization design configurations there is one that fits the heuristic work - adhocracy. The design parameters and coordination mechanisms described in this configuration are following the architectural assumption of autonomy-process-relations materials use, which in turn match the heuristic work characteristics: continuous learning, limited access to information and unpredictability of results. OriginalityThe originality of work is based on researching match between heuristic work and organization design. Literature has not covered this link before. Moreover, the use of architectural assumptions for organization design is differentiating the study from the already performed researches. ImplicationsStudy suggests that following with empirical research requires establishing a number of measures for: heuristic work, organization architecture and organization design. Keywords: heuristic work, algorithmic work, organization design.Classification: Conceptual paper.

Parallel Restarted SGD with Faster Convergence and Less Communication: Demystifying Why Model Averaging Works for Deep Learning

In distributed training of deep neural networks, parallel minibatch SGD is widely used to speed up the training process by using multiple workers. It uses multiple workers to sample local stochastic gradients in parallel, aggregates all gradients in a single server to obtain the average, and updates each worker’s local model using a SGD update with the averaged gradient. Ideally, parallel mini-batch SGD can achieve a linear speed-up of the training time (with respect to the number of workers) compared with SGD over a single worker. However, such linear scalability in practice is significantly limited by the growing demand for gradient communication as more workers are involved. Model averaging, which periodically averages individual models trained over parallel workers, is another common practice used for distributed training of deep neural networks since (Zinkevich et al. 2010) (McDonald, Hall, and Mann 2010). Compared with parallel mini-batch SGD, the communication overhead of model averaging is significantly reduced. Impressively, tremendous experimental works have verified that model averaging can still achieve a good speed-up of the training time as long as the averaging interval is carefully controlled. However, it remains a mystery in theory why such a simple heuristic works so well. This paper provides a thorough and rigorous theoretical study on why model averaging can work as well as parallel mini-batch SGD with significantly less communication overhead.

Family versus couples: How travel goal influences evaluations of bundled travel packages

This research investigates how travel goal activates judgmental heuristics when choosing a travel package. Family travelers must consider the complex needs of all family members, whereas couples face simpler demands. Since motivations vary according to traveling companions, the decision-making processes are different by the travel goal. Pricing is a determinant of decisions for travel packages bundled with add-on items. When the decision process requires less mental effort, the availability heuristic operates when filtering products by travel goal, and the representativeness heuristic works when seeking consistency between add-on items and the travel goal. Dual processing theories suggest that goal influences the motivation to process information systematically or automatically when making choices. An experiment was conducted to examine how the decision-making process differs as a function of travel goal, price bundling, and the consistency between the travel goal and add-on item. The findings suggest that judgmental heuristics influence travel purchase decision when motivation to process information is low. Specifically, the current research supports the proposition that automatic processing influences couples’ travel decisions while systematic processing works for family travel decisions. The research suggests the use of an effective segmentation for vacation packages in the online purchase environment and highlights the importance of a travel goal in decision-making.

The Heuristic Work of the Brain and Artificial Neural Networks

This paper presents two new fundamental principles of the functioning of real neural networks of the brain. These principles have inspired the design of artificial neural networks (a neuro-computer). In addition to well-known properties of artificial neurons (threshold properties, neural network formation, and backward propagation of errors), we describe two new major properties of real neural networks of the brain by which a neuroemulator may work. We discuss the practical usefulness of these properties for the neuro-computer. The first property is permanent statistical chaos in the structure and functions of the brain neural networks. The second property is reverberations, or multiple iterations, in the work of neural networks. The introduction of these two properties to the work of the common artificial neural network provides a new quality, that is, solving the problem of systemic synthesis and finding rank parameters. Modern science has not investigated and solved this problem, which is a general fundamental problem in medicine. It has been shown that this task is identical to the heuristic activity of the brain.

A GPU based local search algorithm for the unweighted and weighted maximum s-plex problems

Given a graph G(V, E) and a value $$s \in {\mathbb {N}}$$, an s-plex S is a subset of V such that each vertex $$v \in S$$ has at least $$|S|-s$$ adjacent vertices in the subgraph induced by S. This work proposes a GPU based local search heuristic, called GPULS, for the problems of finding an s-plex of maximum cardinality and finding an s-plex of maximum weight. The proposed heuristic works well on both problems without any modification on its parameters or its code. GPULS considers two neighborhood structures, which are explored using tabu search and a first-improvement approach. We compare GPULS with the current best-performing exact methods and heuristics. The results obtained by GPULS are highly competitive, even when it runs on a CPU-only architecture. Moreover, we observed speedups of up to 16 times by running the heuristic on a hybrid CPU–GPU architecture.

Load Balancing and Thermal-Aware in Geo-Distributed Cloud Data Centers Based on Vlans

Power consumption in datacenters has become an emerging concern for the cloud providers. This poses enormous challenges for the programmers to motivate new paradigms to enhance the efficiency of cloud resources through designing innovative energy-aware algorithms. However, balancing the weights over geographically dispersed datacenters has been shown to be essential in decreasing the temperature consumption per datacenter. In this paper, we have formulated a load balancing paradigm to exploit the idea of scheduling scientific workflows over distributed cloud resources to make system outcome more efficient. The proposed heuristic works based on three constraints. First, initiating cloud resource locality for tenants and calculating the shortest distance in order to direct module applications to the closet resources and conserving more bandwidth cost. Second, selecting the most temperature aware datacenters based on geographical climate to maintain electricity cost for the providers. Third, running multiple datacenters within the same geographical location instead of housing the entire workloads in a single datacenter. This allows providers to take a tremendous advantage of sustaining the system from degradation or even unpredictable failure which in turn will frustrate the tenants. Furthermore, applications are formulated as Directed Acyclic Graph (DAG)-structured workflow. For the underlying cloud hardware, our model groups the cloud servers to communicate as if they were in the same physical location. Additionally, both modes, on-demand and reservation, are supported in our algorithm. Finally, the simulation showed that our method was able to enhance the utilization rates about 67% compared to the baseline model.

Теорія творчої самореалізації особистості як методологічна основа інноваційної евристичної освіти

The article covers the main stages of development of the conceptual ideas of person’s creative self-realization. The origin of the term "self-realization" is revealed. It has been discovered that the essential ideas of human self-realization were started in the ancient East and Greece and continue to evolve rapidly as the main spiritual needs of every person in the conditions of modern, renewed European civilization. In the article the philosophical views of the national genius G. Skovoroda about self-development and self-realization of the personality are highlighted. According to G. Skovoroda, the use of person’s natural inclinations and abilities in "similar work" is the fundamental foundation of every man’s happy life. It is revealed that the ideas of self-development and self-realization of the personality are the methodological basis of modern innovative education of the heuristic type. The article emphasizes the importance of the successful self-realization of the professional and creative potential of the nowadays teacher in the process of modernizing his professional education. Educators-self-implementers perform heuristic pedagogical activity most successfully. Self-cognition, the ability of cognitive, research, constructive and creative collaboration are the structural components of each participant in an innovative heuristic educational process. It is emphasized that the process of self-development and self-growing is the main part of personal self-realization. Constant changes in the internal and external world of the future teacher lead to the obligatory development of educational heuristic activities – search, reconstructive, constructive, and creative. All participants in the educational heuristic process constantly improve and develop their professional and creative potential, creating specific educational products – the result of their individual and collective heuristic work and at the same time the main indicator of the success of personal self-realization. Keywords: creative self-realization, nowadays teacher, professional creative potential, self-development of the personality, innovative heuristic education, educational heuristic activity.

Rough initial data and the strength of the blue-shift instability on cosmological black holes with Λ > 0

We consider the wave equation on Reissner–Nordström–de Sitter and more generally Kerr–Newman–de Sitter black hole spacetimes with . The strength of the blue-shift instability associated to the Cauchy horizon of these spacetimes has been the subject of much discussion, since—in contrast to the asymptotically flat case—the competition with the decay associated to the region between the event and cosmological horizons is delicate, especially as the extremal limit is approached. Of particular interest is the question as to whether generic, admissible initial data posed on a Cauchy surface lead to solutions whose local (integrated) energy blows up at the Cauchy horizon, for this statement holds in the asymptotically flat case and would correspond precisely to the blow up required by Christodoulou’s formulation of strong cosmic censorship. Some recent heuristic work suggests that the answer is in general negative for solutions arising from sufficiently smooth data, i.e. there exists a certain range of black hole parameters such that for all such data, the arising solutions have finite local (integrated) energy at the Cauchy horizon. In this short note, we shall show in contrast that, by slightly relaxing the smoothness assumption on initial data, we are able to prove the analogue of the Christodoulou statement in the affirmative, i.e. we show that for generic data in our allowed class, the local energy blow-up statement indeed holds at the Cauchy horizon, for all subextremal black hole parameter ranges. We present two distinct proofs. The first is based on an explicit mode construction while the other is softer and uses only time translation invariance of appropriate scattering maps, in analogy with our previous (Dafermos and Shlapentokh-Rothman 2017 Commun. Math. Phys. 350 985–1016). Both proofs use statements concerning the non-triviality of transmission and reflexion, which are easy to infer by o.d.e. techniques and analyticity considerations. Our slightly enlarged class of initial data is still sufficiently regular to ensure both stability and decay properties in the region between the event and cosmological horizons as well as the boundedness and continuous extendibility beyond the Cauchy horizon. This suggests thus that it is finally this class—and not smoother data—which may provide the correct setting to formulate the genericity condition in strong cosmic censorship.

“ZVENO V ZVENO I FORMA V FORMU” (“PART FOR PART AND FORM FOR FORM”): THE METHODOLOGY OF CLOSE READING OF LITERARY TEXT (PART I)

The article considers the methodologies of complex analysis of the text, their loss and gains. The characteristic of “close reading” is given as the method to gain observations on language phenomena and heuristic work on the interpretation of the expressed ideas.

The capacitated hub covering location-routing problem for simultaneous pickup and delivery systems

Abstract In this study, a specific type of hub network topology, called hub location-routing, is presented in which the routes between the nodes assigned to a hub form a tour in this topology. The model minimizes the total cost of hub location and vehicle routing, subject to predefined travel time, hub capacity, vehicle capacity, and simultaneous pickups and deliveries. A polynomial-size mixed integer programming formulation is introduced for the single allocation type of the problems. In this paper, a set of valid inequalities is proposed for the formulation. In addition, a tabu-search based heuristic is suggested which determines the hub location and vehicle routes simultaneously. Series of computational tests are then executed to evaluate the performance of valid inequalities and tabu-search based heuristic. The results show that using all valid inequalities improves the solution time of the pure proposed model. Meanwhile, the proposed heuristic works efficiently in finding good-quality solutions for the proposed hub location-routing model.

En quête de la déviance sexuelle du clergé des Lumières

Enquêter sur la sexualité ecclésiastique au XVIIIe siècle semble d’emblée voué à l’échec. Il est en effet nécessaire de s’interroger sur la définition, poreuse, du clergé et les conditions de sa chasteté. Un tel objet d’études oblige ensuite à renoncer à des prétentions de chiffrage de la déviance, majoritairement restée dans les limbes de l’oubli, quand elle n’est pas au contraire inventée de toute pièce pour perdre un ecclésiastique impopulaire. Le choix d’un corpus dense et éclectique de sources paraît être le plus pertinent pour embrasser toutes les modalités de l’incontinence sexuelle cléricale, et ce d’autant plus qu’il met en lumière un traitement contrasté en fonction des auteurs, des instances, du contexte concerné. En définitive, s’interroger sur la sexualité ecclésiastique entraîne un travail heuristique fécond.

Using conflict and support counts for variable and value ordering in CSPs

A Constraint Satisfaction Problem (CSP) is a very powerful framework for representing and solving constraint problems. Solving a CSP often requires searching for a solution in a large search space. Very often, much of the search efforts are wasted on the part of the search space that does not lead to a solution. Therefore, many search algorithms and heuristic techniques have been proposed to solve CSPs efficiently by guiding the search and reducing its size. Variable and value ordering techniques are among the most efficient ones as past experiments have shown that these heuristics can significantly improve the search performance and lead to the solution sooner. One such heuristic works by gathering information during search to guide subsequent decisions when selecting variables. More precisely, this heuristic gathers and records information about failures in the form of constraint weight during constraint propagation. In this paper, we propose a variant of this heuristic where the weight of a constraint is also based on the conflict and support counts, of each variable attached to this constraint, gathered during constraint propagation. We also propose a dynamic value ordering heuristic based on the support and conflict count information. Experiments have been conducted on random, quasi-random, pattern and real world instances. The test results show that the proposed variable ordering heuristic performs well in the cases of hard random and quasi-random instances. The test results also show that combining the proposed variable and value ordering heuristics can improve the performance significantly for some difficult problems.

Information field for historical research

The article analyzes the main information collision of historical knowledge, which consists in physical inaccessibility of events and phenomena of the past as an object of historical science for a historian as an investigator. The aim of the research is to formulate and discuss a working hypothesis about the information field of historical science. The article provides an analytical background on the main ideas and approaches in the field of modern information field theory. The author carries out the projection of the main provisions of the information field theory on historical research. It is shown that the information field is a really existing information carrier that provides its acquisition, transportation, storage and visualization, as well as provides information and knowledge recorded in various forms, realizes cultural communications. One of the manifestations of such a culture is the sign systems, which determine certain contexts. Signs are characterized by polysemy. Despite artificial origin, semiotic reality is objective. Simultaneously, signs provide intellectual activity of people. Mental signs in the historical process of use by society acquire additional meanings, generating new symbols. Polysemy shapes the problem of epistemological uncertainty of two stages – identifying the problem and solving it. Historians as researchers resort to cognitive models, which, thanks to the translational function, ensure the transfer of information from the known to the unknown. One of the explanations of polysemy is the theory of conceptual integration, according to which the structures of the original mental spaces are projected onto a new, constructed, mental space – blend. This is the result of a personʼs intellectual ability to create new meanings on the basis of the available ones. Since signs and symbols are multi-valued, they form a multiplicity of retrospective scenarios of historical research at the stage of problem formulation. At the stage of its solution, the historian interacts actively with the information field, which consists in verifying empirical data of available scientific hypotheses. At this stage, the historian conducts heuristic, axiological and selection work, which results in the authorʼs version of the historiography.