Request Exchange Research Articles

Dual-channel call center model with exchange of requests and repeat calls

Computer simulation of stationary distribution of states in a call center for a two-channel RQ system with exchange of requests is presented. Such systems are becoming increasingly relevant due to the parallel use of both human dispatchers and voice intelligent bots for servicing calls. The simulation is based on solving the system of stationary Chapman-Kolmogorov equations for the Markov process describing the RQ-system. The system of equations proposed in the work differs from previous models by the presence of an exchange of requests between service channels in accordance with customer preferences. It takes into account the possibility of random repeated calls within a given average time. Service time in channels and delay time of requests in orbits have exponential distribution laws. Requests in orbit have the property of impatience, i.e. leave the system after some random time. To find the stationary distribution of states in orbits, the iterative numerical Gauss-Seidel method is used, which ensures fast convergence of calculations. Each channel has its own orbit of requests. The accuracy of the solution is controlled by increasing the maximum number of requests in orbit until the result stabilizes. The model demonstrates the sensitivity of system performance to the asymmetry of customer preferences when changing channels. Numerical simulation was carried out for the call center of the housing management company "StroyTekhnika" in the city of Voronezh. Application flows and repeat call parameters were calculated based on data from the company website and social network analysis. Accounting for repeat calls reduces system throughput compared to the option of completely impatient customers who do not use repeat calls. The case of completely impatient customers describes the limit state of a service system. At the same time, redistributing calls in favor of a more productive channel improves the overall performance of the system. The results obtained show the feasibility of using high-performance multi-channel voice bots while simultaneously stimulating a shift in customer preferences in favor of intelligent automata.

Transportation in the Sharing Economy

Traditionally, individuals and firms have bought and owned resources. For instance, owning a car was a status symbol for people. In recent years, this focus has changed. Young people just want to have some convenient means of transportation available. Sharing cars, bikes, or rides is also acceptable and has the advantage of increased sustainability compared with everyone owning such a device. A similar development can also be observed in industry. Already for decades, smaller farmers in rural areas have shared some expensive harvesting machines, via cooperatives. In recent years, cost pressures have incentivized all firms to use their equipment more efficiently and to avoid idle capacities. This has led, among other things, to the exchange of transportation requests between smaller carriers, when one of them faces an overload situation and another has idle resources. Similarly, some production firms share storage space and logistics service providers operate this storage jointly with greater efficiency than each firm could do separately. All these tendencies have led to the development of a new paradigm, the “Sharing Economy.” In transportation, these resources are the vehicles used to deliver goods or move passengers. Given an increasing pressure to act economically and ecologically sustainable, efficient mechanisms that help to benefit from idle capacities are on the rise. They are typically organized through digital platforms that facilitate the efficient exchange of goods or services and help cope with data privacy issues. Both transportation companies and heavy users of transportation services need to learn how to play in a world of shared idle capacities. “Transportation in the Sharing Economy” was the theme of the 2019 Transportation Science and Logistics Workshop held in Vienna, and it is therefore also the focus of this associated special issue. The papers included cover several forms of shared resources in transportation, where the first part deals with freight, whereas in the second part, the focus lies on passenger transportation. Each study highlights the benefits of sharing resources. We received 40 submissions, of which 10 papers were accepted for this special issue after the reviewing process.

Comparison of four mechanisms for request exchange in collaborative transportation

AbstractThis paper presents frameworks for auction‐based and posted price mechanisms for exchanging requests between carriers operating in the same geographical areas. Similar mechanisms have been studied before in a rather isolated manner. In this work, all mechanisms are tested within the same scenario and by comparing their results; the aim is to obtain insights regarding the efficiency gains they offer to the network and the required information for their application. Moreover, this comparison provides a clear idea of what is needed to implement each mechanism and the results to expect if one invests in the mentioned implementation, i.e., how much would the net profit be affected. The mechanisms' main objective is to give carriers the chance to improve their original sets of requests in order to increase their overall efficiency. Due to the nature of routing problems, requests usually have different costs for different carriers, depending on the location of the depots as well as on the requests that have to be serviced. The exchange mechanism should find a new allocation such that carriers obtain requests with higher value (i.e., lower cost) for them. Results obtained here show that individual auction‐based mechanisms provide similar results, on average, to centralized auction‐based mechanisms, both outperforming posted price mechanisms. Nevertheless, this improvement difference comes at the cost of providing more information (included in the carriers' bids). Readers can use the presented comparison and results to improve decisions taken prior to collaboration, specifically deciding which mechanism is the best option for a specific situation.

A multi-round exchange mechanism for carrier collaboration in less than truckload transportation

We propose an iterative request exchange mechanism to solve carrier collaboration in less than truckload transportation. In each iteration, each carrier first provides multiple bundles of requests to offer and their corresponding transfer payments. Each carrier then determines which bundles of requests to acquire from one or multiple carriers. Multiple bundles of requests can be exchanged among carriers in each iteration. In each round of the auction, each carrier updates its outsourcing bundles of requests based on the feedback information from previous iterations. Numerical experiments show that this multi-round exchange mechanism provides 11.80% more profit compared to other mechanisms.

Centralized bundle generation in auction-based collaborative transportation

In horizontal collaborations, carriers form coalitions in order to perform parts of their logistics operations jointly. By exchanging transportation requests among each other, they can operate more efficiently and in a more sustainable way. This exchange of requests can be organized through combinatorial auctions, where collaborators submit requests for exchange to a common pool. The requests in the pool are grouped into bundles, and these are offered to participating carriers. From a practical point of view, offering all possible bundles is not manageable, since the number of bundles grows exponentially with the number of traded requests. We show how the complete set of bundles can be efficiently reduced to a subset of attractive ones. For this we define the Bundle Generation Problem (BuGP). The aim is to provide a reduced set of offered bundles that maximizes the total coalition profit, while a feasible assignment of bundles to carriers is guaranteed. The objective function, however, could only be evaluated whether carriers reveal sensitive information, which would be unrealistic. Thus, we develop a proxy for the objective function for assessing the attractiveness of bundles under incomplete information. This is used in a genetic algorithms-based framework that aims at producing attractive and feasible bundles, such that all requirements of the BuGP are met. We achieve very good solution quality, while reducing the computational time for the auction procedure significantly. This is an important step towards running combinatorial auctions of real-world size, which were previously intractable due to their computational complexity. The strengths but also the limitations of the proposed approach are discussed.

Benefits of horizontal cooperation in dial-a-ride services

Dial-a-ride services provide collective on-demand transportation, usually tailored to the needs of people with reduced mobility. This paper investigates the operational effects of horizontal cooperation among dial-a-ride providers. The current practice is that users choose a particular provider to submit their requests. Providers operating in the same area create their routing solutions independently of each other, given their own set of customers. In contrast, horizontal cooperation through joint route planning implies that customer requests can be exchanged among providers in order to minimize the overall routing cost. In addition to quantifying the operational benefits generated by such a horizontal cooperation, this paper identifies operational characteristics that influence the magnitude of the savings. A real-life case study reveals the reasons why providers benefit from certain request exchanges, as well as the extent to which these exchanges are predictable in advance. The solutions are obtained using a large neighborhood search algorithm that performs well on benchmark data.

Economic power transaction using coalitional game strategy in micro‐grids

Due to the uncontrollability of renewable energy resources, micro-grids (MGs) often have to exchange excessive or insufficient power with the utility grid in traditional non-cooperative mode. In contrast, power transaction considering direct energy trading between MGs has been considered as a promising method to improve economic efficiency. Specifically, MGs with complementary power surplus or shortage have an incentive to cooperate with each other and perform direct trading due to lower costs and power losses. In this study, the authors focus on comprehensive economic power transaction of the multiple MGs network with multi-agent system. A three-stage algorithm based on coalitional game strategy is proposed consisting of request exchange stage, merge-and-split stage and cooperative transaction stage. The developed algorithm enables MGs to form coalitions, where each MG can exchange power directly by paying a transmission fee. With local power transaction, MGs can minimise their expenditures comprising the generation costs, transmission costs, power losses and load shedding compensation; hence, ensure the cost efficiency of the whole MGs network. Moreover, the implementation of load shedding is discussed and its benefit is demonstrated. Simulation results show that the proposed cooperative scheme significantly reduces the total cost of MGs compared with the non-cooperative method.

Request selection and exchange approach for carrier collaboration based on auction of a single request

This paper addresses the request selection and exchange problem in the carrier collaboration process with limited sharing of carrier’s request information. A framework including two decision makers, carrier and coordinator, is constructed and its collaboration process is described. In this framework, two request selection models for the carriers are established. In addition, a request exchange method for the coordinator is proposed and four profit allocation strategies are discussed. Compared with other four approaches, simulation results show that the proposed approach is effective and efficient.

Rolling horizon planning for a dynamic collaborative routing problem with full-truckload pickup and delivery requests

In order to improve their operational efficiency, small and mid-sized freight forwarders can establish horizontal coalitions in order to exchange customer requests. Decentralized operational transportation planning processes enabling request exchange among forwarders in spite of information asymmetry and distributed decision-making competences is referred to as collaborative transportation planning (CTP). CTP can help forwarders take advantage of economies of scale and reduce their costs of fulfilling customer requests compared to the case of isolated planning without request exchange. In order to exploit the potential of cost-savings embedded in CTP, appropriate request exchange mechanisms have to be developed. In this paper, the dynamic CTP problem of a coalition of freight forwarders serving full-truckload transport requests is studied. Two rolling horizon planning approaches are proposed to solve the dynamic routing problems. It is analyzed how the planning results, in particular the cost reduction realized by CTP, are influenced by different planning settings. Computational experiments show that the planning results of CTP are considerably superior to those obtained by isolated planning, and the realized cost-savings in percentage remain relatively constant, independently of the test settings.

Portugal: Right to be Notified in Requested State

This book chapter examines comprehensively a Portuguese decision concerning the need to notify the taxpayer before exchanging information with another Contracting State in the framework of tax treaty obligations. This specific case deals with very fundamental issues in terms of the procedural rights of individuals and companies somehow involved in a treaty or EU-based MAP (in casu, exchange of information). A matter that was (conscientiously or not) ignored at the moment when the procedures were designed. The conclusion that the Supreme Administrative Court reached, in its main pillars, is innovative within the Portuguese tax system but goes along with the decisions of many other Supreme Courts in Europe, the ECHR and the ECJ. The conclusion is that supra-national law (ius cogens, fundamental principles of (international) law and positive law) does not provide a sufficient basis for regulating the procedural position of the persons (taxpayer, required subject) involved in a MAP. Neither allows for a judicial review of the decision of the tax authorities that abide by national law, granting the involved persons only the remedies conferred by national law. The current situation may lead to some surprising conclusions. Firstly, and in the context of the same bilateral tax treaty, the position of the person (involved in a MAP) may be quite different in the two contracting states (depending on how they have developed their internal systems of procedural protection of taxpayers). Secondly, if nothing stems from supra-national law, states continue to be entirely free to radically change their internal systems of procedural protection as long as (if they are EU Member States) the changes are done in accordance with the principles of equivalency and effectiveness.[24] Thirdly, and even if this was not anticipated by those who designed the current rules, the absence of regulation at the person level may even harm the validity of the information exchanged itself. This can happen, for instance, when the requesting state and the requested state adopt different standards for the protection of taxpayers' rights. For instance, if the requesting state requires some audition or grants intervention rights of the taxpayer at the moment of gathering evidence and those conditions are not foreseen in the requested state, the requested state will collect all information without any intervention of the taxpayer, which, in the end, may claim that the evidence gathered was not in line with the procedural rights in force in the requesting state. And, as we are dealing with different jurisdictions, there is hardly the possibility of any novatio or reform of the procedure. The deficiencies of this mode of creation of supra-national law should also be noted. The current system of mutual assistance is the result of the sedimentation of several changes that were based on the assumption that all that matters is the horizontal relations between states. As the previous comments show, this seems to be a deficient way of regulating matters, particularly at the tax treaty level, where no higher jurisdiction will be responsible for a consistent and harmonized interpretation. Moreover, it is the author's opinion that the rule of law, and in particular the idea of predominance of the individual in the construction of legal rules, prevents a system where the individual appears completely abandoned, being the object of several duties and obligations but deprived of any added protection. This objectification of the regulation seems to be in contradiction with most legal philosophers of the last half century. It is urgent for supra-national law to set minimal standards in this field. Standards that would ensure that, regardless of what happens in domestic law, there is a minimum densification of the rule of law and in particular of the right to be heard. This densification is even more pressing in the framework of EU law as the system currently in force allows for a substantive increase of exchange of information requests, which needs to be safeguarded by a sound system of procedural protection of the citizen.

“Just bring me a little letter”: the flow of things in Cape Verde transnational family relations

This article discusses the ways people strengthen and maintain their sense of belonging to concrete or imagined places or groups via communication networks. It focuses on the flow of things through transnational networks between Cape Verdean migrants and their relatives at home. It is an intense and diversified network involving kinship ties in a context of prolonged physical distance in both space and time. The flows in question consolidate social, cultural, and family networks between migrants and their home communities in a complex system of exchange and circulation of gifts, requests, money, and information that mobilize those who leave and those who stay. The argument is based on the dialogue between ethnographic data and works that have explored transnational flows of people, capital, and goods within the globalization framework.

Vehicle Routing under Consideration of Transhipment in Horizontal Coalitions of Freight Carriers

In order to reduce operational costs related to transportation activities in road haulage, small and medium-sized freight carriers can establish horizontal coalitions and share their resources. Through exchange of customer requests with other members within the coalition, carriers can improve the operational efficiency of their transportation processes. In this paper, transhipment is integrated into the conventional pickup and delivery problem in the collaborative context. Specifically, vehicles involved in transferring the same request are synchronized at the transhipment points. A mixed-integer programming model is proposed for this problem. Based on this model the benefits of transhipment are analysed. Computational results show considerable cost-savings enabled by transhipment in the operational planning of carrier coalitions.

Collaborative transportation planning of less-than-truckload freight

Collaborative transportation planning (CTP) within a coalition of small and medium-sized freight carriers can be used as a powerful instrument to improve the operational efficiency of the coalition members. In such coalitions, transportation requests from different carriers are exchanged in order to reduce the total fulfillment costs. In this paper, the CTP for a set of independent carriers exchanging less-than-truckload transportation requests is considered. The realistic restriction that all collaborating partners have only limited capacities in their fleets is included in the consideration. To keep their autonomy, coalition members keep their sensitive information including customer payments and cost structures unexposed during CTP. A new decentralized request exchange mechanism for CTP is proposed while only vehicle routes are considered for exchange. It is tested on some newly generated instances and the CTP solutions are compared with those obtained by isolated planning without collaboration and those obtained by a heuristic approach for the centralized planning problem. The results indicate that our mechanism is very efficient and effective in terms of realizing potential cost-savings by CTP, even when capacity limitations and restrictions on the exposure of information are explicitly considered.

The Swiss Tax Ruling Procedure: Interplay with Exchange of Information Requests

Over the course of two articles, the authors examine the Swiss ruling procedure. The first article, published in the September issue of European Taxation, examined the conceptual background of the procedure from a domestic law perspective. This second article analyses whether or not a ruling, or information provided in the course of a ruling, confirmed by a Swiss tax administration, can be the object of an exchange of information request.

Assessment of Taxes in Cross-Border Situations: The New EU Directive on Administrative Cooperation in the Field of Taxation

This article discusses a recently adopted European Union (EU) Directive that, from 1 January 2013, will gradually introduce important changes to the EU regulatory framework on cross-border mutual assistance in the assessment of taxes. The new Directive broadens the scope of mutual assistance and improves its efficiency, notably as regards information exchange on request and automatic exchange of information. It also introduces comitology for the first time in the area of direct taxation.

Stroke in Sickle Cell Anemia After Excellent Response to Hydroxyurea.

Abstract 4622 IntroductionStrokes occur in about 10% of children with sickle cell anemia (SS) less than 10 years old. These strokes are usually ischemic in nature. Stroke due to SS in adults is less common and is usually hemorrhagic in nature. We wish to report an unusual adult patient with SS and excellent response to HU who developed a stroke that was unrelated to SS. Case Report and ResultsA 35-year-old female with sickle cell anemia had mitral valve prolapse and migraine headaches presented 2 days after developing abrupt bilateral blurry vision, left facial numbness and weakness of her left leg. Her SS has been complicated by acute chest syndrome, bilateral hip avascular necrosis and frequent painful crises prior to hydroxyurea (HU) therapy. She was enrolled in the multicenter study of hydroxyurea (MSH) in SS and has been on 2500mg of HU per day for the past 13 years. She had an excellent response to HU with no recurrent acute chest syndrome and decreased need for blood transfusion. After starting HU, the frequency of crises requiring hospital admission decreased from 1 admission every 1 to 2 months to less than 1 admission per year except when hydroxyurea was discontinued for pregnancy. Her fetal hemoglobin increased from 6.1 % before HU to a maximum of 45%. Her MCV increased from 96 fl to a maximum of 132 fl and Hb from 8.0 g/dl to 9.8 g/dl Her exam was remarkable for left lower extremity weakness which was more pronounced proximally. All cranial nerves were intact and there was normal sensation bilaterally. CT scan of the brain showed three foci of hypodensity and MRI of the brain showed increased signal on T2, FLAIR and diffusion weighted images within the frontoparietal deep white matter consistent with infarction in the border zone of the middle cerebral artery (MCA)-anterior cerebral artery (ACA). MR angiography of the intracerebral and extracerebral vessels demonstrated focal narrowing of the right MCA at the trifurcation suggesting an embolic cause. Common causes of stroke were ruled out with routine studies. Her hemoglobin electrophoresis after admission but before blood exchange transfusion showed HbS of 55% and HbF of 45%. She underwent exchange transfusion 2 days after admission and was started on chronic blood exchange transfusions with the assumption that she had ischemic stroke due to SS. Initial transthoracic echocardiogram with contrast injection did not show an atrial shunt. Follow-up transesophageal echocardiogram after discharge showed a secundum atrial septal defect with a defect size of 1.4 cm. Right heart catheterization was performed and the pulmonary flow to systemic flow (Qp/Qs) was 1.7:1. An Amplatzer atrial septal defect (ASD) closure device was deployed with transesophageal echocardiographic guidance and a large thrombus was removed from the right atrium. At the patient's request exchange red cell transfusions were discontinued. The patient has continued treatment with hydroxyurea and aspirin. ConclusionsYoung patients with cryptogenic stroke have a much higher prevalence of atrial shunts and in particular patent foramen ovale than patients with other forms of stroke and therefore a cause-effect association is suggested. Young adults with stroke should be evaluated for common and reversible causes of stroke including paroxysmal emboli. Transesophageal echocardiography is the gold standard for diagnosing atrial shunts. Strokes in patients younger than age 55 are related to paroxysmal emboli and have a risk of recurrence of approximately 30% within one year. High risk features for stroke recurrence with an atrial shunt include hypercoagulable states, large opening and presence of an atrial septal aneurysm. Optimal management of patients with a stroke and an atrial shunt is unknown. Options include surgical closure, percutaneous device closure, anticoagulation and antiplatelet therapy. Patients with sickle cell disease and stroke should receive long term blood transfusions to reduce HbS below 30% if the stroke is felt to be related to sickle cell disease vasculopathy. The patient described with SS had a stroke and had an atrial septal defect that was repaired. The MRI/MRA findings are consistent with paroxysmal emboli. The patient is receiving treatment with hydroxyurea and aspirin having discontinued red cell exchange transfusions and at two years of follow-up has not had a recurrent stroke. Disclosures:No relevant conflicts of interest to declare.

Greater cooperation and transparency in the Cayman Islands

On 18 February 2009, the Cayman Islands Monetary Authority (CIMA) signed a formal Memorandum of Understanding with its Maltese counterpart, the Malta Financial Services Authority. The Memorandum puts in place a framework intended to promote mutual cooperation between the two regulators in relation to the exchange of information and requests for assistance over enforcement matters. It formalizes a relationship that had been taking place on an informal basis for some time and brings the total number of such agreements entered into by CIMA to 14. Following on from this, on 11 March 2009, the government of the Cayman Islands announced that it has reached bilateral agreements, including tax information exchange agreements, with the governments of seven Nordic countries (Denmark, the Faroe Islands, Finland, Greenland, Iceland, Norway and Sweden). These bilateral agreements are the result of negotiations between each of the Nordic governments and the government of the Cayman Islands that have been ongoing since April 2008. The full content of the agreements will be available on execution by the respective governments in April and June 2009. In addition, on 19 March, the government announced that it has unilaterally extended comprehensive tax information assistance to Germany, Austria, Belgium, Czech Republic, Luxembourg, Slovak Republic and Switzerland in relation to civil, administrative and criminal tax matters.

Optimal management of logistic activities in multi-site environments

The new emerging area of Enterprise Wide Optimization (EWO) has focused the attention in effectively solving the combined production/distribution scheduling problem. The importance of logistic activities performed in multi-site environments comes from the relative magnitude of the associated transportation costs and the good chance of getting large savings on such expenses. This paper first develops an exact MILP mathematical formulation for the multiple vehicle time-window-constrained pickup and delivery (MVPDPTW) problem. The approach is able to account for many-to-many transportation requests, pure pickup and delivery tasks, heterogeneous vehicles and multiple depots. Optimal solutions for a variety of benchmark problems with cluster/random distributions of pickup and delivery locations and limited sizes in terms of customer requests and vehicles have been discovered. However, the computational cost exponentially grows with the number of requests. For large-scale m-PDPTW problems, a local search improvement algorithm steadily providing a better solution through two evolutionary steps is also presented. A neighborhood structure around the starting solution is generated by first allowing multiple request exchanges among nearby trips and then permitting the reordering of nodes on every individual route. If a better set of routes is found, both steps are repeated until no improved solution is discovered. Compact MILP mathematical formulations for both sub-problems have been developed and solved through an efficient branch-and-bound algorithm. A significant number of large-scale m-PDPTW benchmark problems, some of them including up to 100 transportation requests, were successfully solved in reasonable CPU times.

06/01687 System reliability worth assessment at a midwest utility — survey results for residential customers: Chowdhury, A. A. et al. International Journal of Electrical Power & Energy Systems, 2005, 27, (9–10), 669–673

The new emerging area of Enterprise Wide Optimization (EWO) has focused the attention in effectively solving the combined production/distribution scheduling problem. The importance of logistic activities performed in multi-site environments comes from the relative magnitude of the associated transportation costs and the good chance of getting large savings on such expenses. This paper first develops an exact MILP mathematical formulation for the multiple vehicle time-window-constrained pickup and delivery (MVPDPTW) problem. The approach is able to account for many-to-many transportation requests, pure pickup and delivery tasks, heterogeneous vehicles and multiple depots. Optimal solutions for a variety of benchmark problems with cluster/random distributions of pickup and delivery locations and limited sizes in terms of customer requests and vehicles have been discovered. However, the computational cost exponentially grows with the number of requests. For large-scale m-PDPTW problems, a local search improvement algorithm steadily providing a better solution through two evolutionary steps is also presented. A neighborhood structure around the starting solution is generated by first allowing multiple request exchanges among nearby trips and then permitting the reordering of nodes on every individual route. If a better set of routes is found, both steps are repeated until no improved solution is discovered. Compact MILP mathematical formulations for both sub-problems have been developed and solved through an efficient branch-and-bound algorithm. A significant number of large-scale m-PDPTW benchmark problems, some of them including up to 100 transportation requests, were successfully solved in reasonable CPU times.

A STEP AP224 agent-based early manufacturability assessment environment using XML

Early design assessment activities have a significant impact on reducing the cost of manufacture. The efficient utilisation of the product development time and the level of coordination of the early design activities between the major stakeholders are becoming key factors for success in manufacturing today. The paper reports on a new distributed early design manufacturability assessment methodology using collaborative autonomous agents. A product data model compliant with STEP AP224 and corresponding process and facility data models are proposed to support the decision-making process. XML was used as a medium for exchange of requests and information between design, manufacturing, and facility planning agents. A prototype Web-enabled system for rapid product manufacturability assessment in the extended enterprise has been developed using distributed multi-agent CORBA objects. The reported research is a step towards the development of a generic prototype tool for collaborative design evaluation and rapid assessment of the manufacturing feasibility and resource availability at different stages of the product development process.