Showing papers presented at "International Conference on Service Operations and Logistics, and Informatics in 2009"

Modeling and integration of hospital information systems with Petri nets

Abstract: While the use of information technologies is becoming increasingly widespread in healthcare organizations, such as large hospitals, to date these organizations lack unified information systems providing a comprehensive view of the organization's state. We define a technique for building formal models capturing the state of hospital departments and the interactions among departments during hospital operations. These models, based on Petri nets, will support a variety of management and decision-support tools, such as statistical analysis, simulation, and dynamic reconfiguration. These models are at the core of a new software prototype that we are developing for the University of Illinois Medical Center at Chicago.

Embedding the new discipline of service science: A service science research agenda

Abstract: This paper presents a discourse for embedding the new discipline of service science. It argues for service science to be free of the paradigmatic research influences of existing disciplines and propose service science as an integrative discipline of engineering, technological and social sciences (including business and law) for the purpose of value cocreation with customers. The paper proposes a research agenda for service science and considers five salient issues for knowledge production. It locates the argument for service science knowledge production alongside disciplinary knowledge of service and in so doing, suggests that service science is not a logical development within any discipline and proposes that the time is right for it to emerge into a discipline of its own.

Integrating supply chain management concept in a goods movement microsimulation

Abstract: Freight transportation systems are usually modeled in a framework, primarily designed for passenger transportation. The objective of the study presented in this paper is to introduce a behavioral freight modeling framework, in which the role of firms as the decision making agents is emphasized. This framework simulates the goods movement through the supply chains in five modules: Firm Generation, Supply Chain Replication, Shipment Forecasting, Logistics Planning, and Network Analysis. Second and forth modules are the essence of this behavioral model, but are usually ignored in almost all the current frameworks. To have the framework running, the data requirements are also discussed. Some useful and publicly available datasets in the US are explained along with a proposition for an additional online survey. Primary objective of this survey is to gather needed information on the commodities shipping process, which is missing in the available datasets. Pilot survey's results and some descriptive statistics are also provided.

Intersection traffic control by a novel scheduling model

Abstract: This paper proposes a new scheduling model for controlling traffic at intersection. These controls are based on new information and communication systems and perform to take into account all vehicle arrivals individually. Vehicles negotiate their time of access through an intelligent device embedded in the intersection, hence there is no traffic light planned by the city. The objective of control is to evacuate all vehicles as soon as possible while considering the emergence of important vehicles. The intersection control becomes to determine the best access order to the intersection for all vehicles which are approaching it. Since the intersection is a scare resource shared by vehicles, the problem of control can be solved by a novel scheduling model proposed in this paper.

Consensus value of multi-agent networked systems with time-delay

Abstract: In this paper, we investigate two classes of consensus protocols for networked multi-agent systems: linear time-invariant (LTI) systems and linear time-delay systems. Based on the topology of multi-agent systems, the first-order integrator model is developed. The digraph (directed graph) is employed to show the topology of networked systems, and then a consensus convergence criterion is established. For LTI systems, we prove that their consensus value will converge globally asymptotically to the convex hull of initial states. By solving a set of linear equations, we get the convex combinations of equilibria, and we obtain the convex value of continuous system. If the topology is fixed and time-invariant, the consensus value of the linear time-delay system is also the convex hull of the initial states and is identical to the LTI system. Finally, a network of six agents is presented to show the effectiveness of the results of this paper.

Gateway Deployment Optimization in Wireless Mesh Network: A Case Study in China

Abstract: The rapid development of communication technology provides a enormous support for municipal mesh network. Nowadays many cities across the world have setup or prepare to setup wireless mesh networks (WMNs), includes Beijing city for its 2008 Olympic Games. However, Internet Gateway (IGW) placement, which is one of essential issues in a WMN design, has not been considered seriously in practice both by equipment provider and planning institute. Taking Beijing Wangjing zone as an example, the actual placement results didn't consider the gateway deployment optimization. This paper, first formulates its IGW placement problem as an integer linear programming incorporating QoS into account. Then solves the problem using Degree-based GDTSP algorithm proposed by [6] and compares the results with the existent ones given by Chinacomm planning institute. After that, the paper presents a new heuristic algorithm adapt to a special type of graphs in practice, and new results analysis shows that it can help to save more than 25% of the system cost.

A new hybrid variable-length GA and PSO algorithm in continuous facility location problem with capacity and service level constraints

Abstract: This paper considers a continuous capacitated facility location problem without a priori knowledge of the desired number of facilities. The demand locations and volume are known to the decision maker. A new hybrid evolutionary algorithm combining variable-length GA (Genetic Algorithm) and PSO (Particle Swarm Optimization) together is proposed to solve the problem. For variable-length GA, the chromosome in the population varies with the number of facilities to be located, and special crossover and mutation operators are designed. For PSO algorithm, it is combined with ATL (Alternative Transporting Location) method to attain the appropriate location of each facility. Furthermore, an external population is adopted to gather the inferior solutions instead of abandoning them simply. This work has been developed as an Eclipse RCP tool and applied in business cases.

Virtual Emergency Preparedness Planning Using Second Life

Abstract: A team from the University of Illinois at Chicago, School of Public Health CADE (Center for the Advancement of Distance Education) has created a training archipelago called Public Health Preparedness. The island chain offers a variety of urban and rural environments with customized buildings, objects, and scripting tailored to emergency scenarios ranging from pandemic influenza to bio-terrorism and dirty bombs. Training exercises began in late 2006. Current training is primarily in the form of facilitated exercises allowing federal, state, and local workers as well as emergency volunteers to conduct a wide variety of virtual operations in support of Planning, Training, and Evaluation. There are terrific advantages in using Second Life to conduct many exercises virtually instead of live or in other traditional training modes (like tabletops). We predict that within two years a large portion of Emergency Preparedness Training exercises will be conducted virtually.

An empirical comparison of five efficient heuristics for Maximal Covering Location Problems

Abstract: Facility location decision is a critical element in strategic planning for a wide range of public sector and business world. Maximal Covering Location Problem (MCLP) is one of the well-known models for facility location problems. Algorithms to optimally solve this kind of practical operational management problem often suffer from the combinatorial explosion when the system size increases. In these cases, heuristic methods are the only viable alternative. A lot of work has been devoted to the study of heuristics for MCLP. But there lacks a complete comparison of different methods. In this paper, we compare the relative performance of five efficient heuristic methods: Greed-Add, Interchange, Efficient Genetic Algorithm (GA), Efficient Tabu Search (TS), and Efficient Simulated Annealing (SA). The results indicate: Greedy-Add can achieve relatively good solutions in a very short time; GA-based algorithm performs not as successfully as it used to do in most combinatorial problems; and Efficient SA always gets the best solution among all the five algorithms. Thus, in general we may conclude that Efficient SA should often be tried first for this kind of problems.

On flexibility and sustainability in container ports

Abstract: The aim of this paper is to link flexibility and sustainable advantages together in the context of container harbors. First, a definition of the flexibility concept, its dimensions and metrics are given; second, a discussion of the relation between flexibility, multimodality and sustainability is conducted. It is argued that multimodal transportation adds value into the whole supply chain and thus is an enabler for flexibility. However, there is an increase in environmental challenges which should be addressed proactively throughout the whole supply chain. Third, some measures that increase the container port's sustainability are described; and last, the case of Narvik container harbor is outlined.

Comparison of mitigation strategies for supplier risks: A multi agent-based simulation approach

Abstract: Experiments on simulation models were conducted to determine appropriate risk mitigation strategies for a supply chain network under supplier risks. To model the supply chain network, an agent-based simulation model was designed and implemented using the Unified Modeling Language (UML) standard and Java Agent DEvelopment (JADE) platform respectively. In order to model the risks in the simulation models, unexpected events were randomly generated to mimic the risks that possibly occur in the supply chain. Particularly, four types of risks were considered, including rare and short, rare but long, frequent but short, and frequent and long risks. In addition, two risk mitigation strategies, i.e. having a redundant supplier and reserving more inventory, were applied and compared. By considering average total operating cost and average product shortage, results are generated for appropriate mitigation strategy for each type of risk.

Modelling, variation monitoring, analyzing, reasoning for intelligently reconfigurable Clinical Pathway

Abstract: Aimed at the variations of CP, combined modular modelling method and structure changing mechanisms, a Modular Colored Petri Net with changeable structure (MCPN-CS) workflow modelling method is proposed. A new type of place, namely signal place, is added into the MCPN-CS to respond the variation states of CP. Meanwhile, a hybrid variation monitoring and an analyzing and reasoning controller are designed. Therefore, according to the real-time variation status, the workflow model for CP can be reconfigured intelligently by using the mechanism of change-by-modification (CBM) and change-by-composition (CBC). A case study on osteosarcoma CP evolution workflow modelling is give to validate the proposed method.

A novel parking service using wireless networks

Abstract: Parking is costly and limited in almost every major city in the world. The misparking aggravates the competition of parking slots. Innovative parking systems for meeting near-term parking demand are needed. A probabilistic approach is addressed to model the misparking of the current parking system. To provide an intelligent parking services and to eliminate the misparking, a wireless-based parking service is proposed. The proposed system adopts the wireless network and sensor technologies to provide an intelligent and automatic parking service. The implementation and a probabilistic analysis of the new parking service are presented as well.

Density aware routing using road hierarchy for vehicular networks

Abstract: Inter-vehicular communication (or Vehicular Adhoc Networks, VANET) mirrors as one of the emerging technologies for road safety and comfort applications. However the use of this technology is limited due to the lack of an efficient routing protocol. In this paper we propose Density Aware Routing using Road Hierarchy (DAR-RH) which is based on realistic road topology. DAR-RH exploits the available road hierarchy information to transfer data from source to destination. In the proposed solution two routes are maintained; in case of failure of the primary route, an alternative route is maintained at a higher hierarchy under sparse network conditions. The proposed scheme is found to exhibit significant performance improvement in comparison with a geographic routing protocol under similar conditions.

Knowledge-based hybrid variance handling for patient care workflows based on clinical pathways

Abstract: Variance handling plays a key role in the computerized clinical pathway (CP) management enabling high-quality and efficient patient care processes and healthcare services. Based on the analyses of the classifications and handling characteristics of variances, this paper proposes a hybrid variance handling approach combing generalized fuzzy ECA (GFECA) rules and a typed fuzzy Petri net extended by process knowledge (TFPN-PK) model to effectively support handling decisions of different types of variances. A prototype system is developed to implement the proposed approach and facilitate dynamic management of CP-based healthcare workflows.

Optimization Model For Distributed Routing For Disaster Area Logistics

Abstract: The problem of transportation in a disaster area can be seen broadly as having two aspects: (a) moving people and materials out of an area, and (b) moving people and materiel into the same area. The common thread here is the use of a limited set of surface and air transportation gateways into and out of the area. The distributed routing problem here is that of assigning one from among the limited set of gateways to various transportation requests in real-time, while maximizing some measure of success for the entire relief mission. We define the general problem, provide an example of the real-time transportation routing problem, and propose an optimization model. The similarity of this problem to a job shop scheduling problem is presented pointing to the fact that a distributed approach based on bio-inspired methods can be developed to counter the large problem size and centralized nature of the integer multi-commodity network model. A small illustrative model of the integer multi-commodity network model is presented and solved

Prediction model of supply chain demand based on fuzzy neural network with chaotic time series

Abstract: In order to quickly determine and control the chaotic oscillation in supply chain system, to enhance the prediction accuracy of supply chain demand, and ensure the stability of supply chain systems, using fuzzy neural networks based on chaotic time series, sub-phase space is rebuilt by the demand time-series of supply chain system. Calculating the phase-space saturated embedding dimension and the largest Lyapunov index. Prediction model of supply chain demand has been built by fuzzy neural network based on a chaotic time series. The chaotic phenomena has been judged in supply chain system. Supply chain demand prediction controller has been designed based on fuzzy neural network. The simulating results show that fuzzy neural network with chaotic time series is feasible and effective on prediction of supply chain demand.

An evaluation method of operational effectiveness for the emergency plans

Abstract: It is difficult to select a feasible rescue plan from many plans when an emergency disaster is suddenly occurred. The main reason is that there is no well decision-making means to support. Considering the characteristics of the emergency disasters, an evaluation method on the operational effectiveness of the emergency plans is put forth. And the simulation of the emergency disaster process is adopted to collect the information about the disaster situation. Then some proper utility functions are built up to evaluate the operational effectiveness of the emergency plans. As an example, a scenario of a strong earthquake disaster is built, by means of the evaluation method, and the best alternative is finally gotten. The evaluation results show that the evaluation method is feasible and meaningful.

Hybrid nested Partitions And Relax-And-Fix approach for capacitated multi-item lot sizing problem

Abstract: In this paper we consider the capacitated multi-item lot sizing problem with setup times. The problem is to schedule N different items over a horizon of T periods with the objective to minimize the sum of setup cost and inventory holding cost. To achieve feasible high quality solutions, we propose a hybird solution approach which integrates Nested Partitions and Relax-and-Fix. Nested Partitions is a partitioning and sampling based heuristic method with a global perspective on the problem. Relax-and-Fix is implemented to obtain good promising regions and speed up the computational process. Computational results based on benchmark test problems show that the approach is computationally tractable and is able to obtain good results. The approach outperforms other state-of-the-art approaches found in the literature.

Hospital stockpiling for influenza pandemics with pre-determined response levels

Abstract: This paper explores the problem of hospital stock-piling of critical medical supplies in preparation for a possible influenza pandemic.We consider a regional network of hospitals that have mutual aid agreements in place such that they may borrow or lend supplies from each other during medical emergencies. We assume that the attack rate is a random variable with known distribution and that the demand surge due to the pandemic is a function of the attack rate, and is thus stochastic. We further assume that each hospital in the network pre-determines its targeted pandemic response level, and that any demand beyond this pre-determined level is reallocated to other hospitals. Each hospital in the network must decide the stockpile level that minimizes its expected overall cost, including purchasing cost, holding cost, cost (revenue) for borrowing (lending), penalty for setting a too low targeted level, and shortage penalty. To capture the mutual aid relationships of hospitals in the network, we formulate the problem as a game theoretic model. We show that the response sets are nested and we provide an algorithm to obtain numerically the Nash Equilibrium solution of this game. We illustrate the structure of the model on a two-hospital example and perform sensitivity analysis with respect to parameters of our model.

New approach in supplier selection using linear physical programming

Abstract: Newly, outsourcing has become the superior part of any company. The activities which are not economical to the business or not feasible to manufacture in-house are being outsourced to suitable suppliers. The major barrier in outsourcing is to select a suitable supplier. The selection of suppliers depends on a firm's criterion and it is almost impossible that one supplier satisfies the entire criterion that a firm concerns. The challenge is to optimize selection process based on critical criteria and select the best supplier(s). The supplier selection problems (SCPS) are multi-objective problems and no single methodology can be useful in solving supplier selection problem (SCP). In this paper the author focuses on supplier selection problem in three echelon supply chain with supplier, retailer (we name it buyer here) and customer using linear physical programming approach.

Understanding supply chain robustness

Abstract: This paper reviews important concepts behind supply chain (SC) problems and instability, which lead to the need to design and operate more robust supply chains. Based on several works reviewed, a supply chain is considered robust when it is insensitive to variations or noises in not so regular operating conditions. Those adopting robust-oriented approaches (techniques) will have more chance to stay successful in the market.

Study on The construction and development of Shanghai E-port system

Abstract: The construction and development of Shanghai e-port system is studied in this paper based on the electronic customs declaration and the electronic payment platform. It is especially analyzed how to improve the economic effectiveness and social benefits of local international logistics informationization since the implementation of Shanghai e-port, such as strengthening the customs supervision, speeding up the flow of imports and exports, expanding the scope of Shanghai logistics center, etc. Finally, some measures are proposed to further expand the value of Shanghai e-port system, including the port innovative model, and other regional collaboration strategies.

Customer-centric optimal resource reconfiguration for service outlets

Abstract: How to optimally configure its service resources is always a key for the service providers to improve efficiency and quality of service. Fail to optimize service capability often causes long queues in many on-site service outlets, for example, retail stores, bank branches or government agencies. A first step to do service capability configuration is to identify and understand customer demand and preference. In previous research, these metrics are often obtained by general high-level (e.g. city level or district level) surveys which are not detailed enough for modeling specific customer experience at a given site. Further more, customer satisfaction is not considered as a key objective compared to cost and profit, which often leads to decisions that do not accommodate customer experiences adequately. A deep understanding of customer behavior will greatly help service providers achieve the commercial transformation from product-centric to customer-centric and enhance their market share and competitive strength. In this paper, we propose a customer-centric service resource reconfiguration method which identifies customer demand and preference from internal historical transaction data. Agent simulation is adopted to model the stochastic service processes and customer behavior in optimizing service resources.

A systems approach for balancing internal company capability and external client demand for integrated product-service solutions

Abstract: This paper offers a systems thinking approach for easing the tension between the front office (responsible for meeting client requirements) and the back office (responsible for providing necessary company capabilities) in the transformation of a product-focused company to a product-service provider. These parts of the company may have competing objectives and cultures that must be reconciled to ease the train of tension between them. We propose consideration of these parts as individual systems within a system of systems construct and suggest the creation of a central function as a third system, the purpose of which is to manage the interoperability between the front and back offices. The central function provides a leadership role and an integrating function for the company, the outcome of which should be firstly to act as a catalyst for changing the mindset of individuals within the organization towards the product-service endeavour and, secondly, a strategic balance in terms of implementing policy in accordance with the changing external business environment. The management of this balance between the product system and the service system within the same organization is a crucial element of sustainability.

Hierarchical and centralized architectures for distributed production planning, scheduling and control activities

Abstract: This work reviews some of the basic ideas behind centralized and hierarchical architecture, especially focusing on internal logistics activities. It also bring initial thoughts for a methodology to help select (or design) control architecture for distributed production planning, scheduling and control. This methodology would focus on two main aspects: (1) a response-time based approach to be used as the input to measure the effect of different CAs in the system performance, and (2) an activity-based approach for the creation of simulation and control models.

Consumer motivation and site transfer behavior: Weblog analysis for online service

Abstract: Online consumers visit retail websites in two venues: 1) Direct access by input of known URL addresses or 2) indirect access by clicking the links from third party websites. This research is an exploratory investigation on why online consumers access retail websites with each of the distinctive access manners and how it influences purchase decision-making processes: to purchase or to browse. In detail, it is assumed that the website access manners are affected by different web site visit motivations of goal-directed versus exploratory type. Unlike off-line store environments, it is possible to track online consumers' detailed behaviors by looking at the records saved in Web server log files. The present study utilizes the 3,885 clickstream data in Web log files, and attempts to investigate the differences in purchasing related activities between the distinctive access types. In further, we also consider the product involvement level to examine whether the differences between the two groups are affected by the degree of product level involvement. The empirical findings indicate that online consumers with direct access manner tend to display the characteristics of goal-directed shoppers. In comparison, the referred group of customers is associated with exploratory tendencies. The product involvement level is only effective in direct access group.

A RFID model of transferring and tracking trauma patients after a large disaster

Abstract: Disaster management is always an important issue of international studies. A large disaster always generates numerous trauma patients in a very short time. Thus, how to ship these patients to appropriate hospitals in time so as to save their lives is an important issue. This study uses the GIS interface to construct a medical decision support system for Kaoshung city, in which the available medical recourses are dynamically updated by RFID system. The goal of this system is optimizing the shipment of patients by minimizing the transportation and operation time by dynamic programming. This model achieves a small success with an example of two hospitals so far, which is executed by a server-client framework by integrating GIS, VBA and RFID altogether. The prototype model will be extended for practical uses for Kaoshung city of Taiwan in the very near future. Decision maker is able to simulate the exercise performance in this system.

Web portal quality

Abstract: The purpose of this study is to review the characteristics of Web portal quality from the end-users' perspective and to propose a web portal quality model. In this study, the quality of web portals consists of three basic components: the information content (e.g., accuracy and applicability), the physical medium (e.g., timeliness and speed), and the service (e.g., reliability and responsiveness of the product provider).

Optimal batch production with minimum rework cycles and constraint on accumulated defective units

Abstract: This paper deals with the issue of economic batch quantity (EBQ) in a single machine system in which defective items are produced in each cycle of production. The accumulated defective items produced in a period, consisting of several equal cycles, are all reworked in the last cycle of this period called the rework cycle. At the end of each period the whole process will start all over again. We assume that there is a limitation on the total defective items. We also do not adopt the restriction that the rework process rate be equal to the normal production rate. In addition we assume that there is a set up time for rework process. Further we assume that the number of rework cycles be as small as possible, which is mainly due to changeover costs needed for going from normal production to rework as well as special attention required for rework to satisfy the zero defect criterion. Finally, for the ease of production and resource planning, the rework cycle has to have the same length as the other cycles. For this system, assuming no shortages are permitted we obtain the economic batch quantity which minimizes the total cost of the system.