EunSu Lee

Designing Service Coverage and Measuring Accessibility and Serviceability of Rural and Small Urban Ambulance Systems

This paper proposes a novel approach to analyze potential accessibility to ambulance services by combining the demand-covered-ratio and potential serviceability with the ambulance-covering-ratio. A Geographic Information System (GIS)-based spatial analysis will assist ambulance service planners and designers to assess and provide rational service coverage based on simulated random incidents. The proposed analytical model is compared to the gravity-based two-step floating catchment area method. The study found that the proposed model could efficiently identify under-covered and overlapped ambulance service coverage to improve service quality, timeliness, and efficiency. The spatial accessibility and serviceability identified with geospatial random events show that the model is able to plan rational ambulance service coverage in consideration of households and travel time. The model can be applied to both regional and statewide coverage plans to aid the interpretation of those plans.

Simulation of a base stock inventory management system integrated with transportation strategies of a logistic network

A logistics network management system controlling the entire supply chain was designed to reduce the total cost and to achieve an efficient system. The interactions between inventory and transportation strategies in the logistics network are presented in this paper. Demand volumes and shipping sizes were simulated as part of a new conceptual model by using a discrete event simulation to minimize the total cost in the supply chain. The experiments indicate that the Full Truckload scenario leads to cost-efficiency and the larger demand size results in smaller cost per unit based on economies of scale. Considering the interaction effects, the demand size has a greater impact on the cost reduction than the shipping size.

Simplistic Geospatial Techniques in Analyzing Transportation Dynamics for Origin-Destination Container Movement Routes in the United States

Abstract Spatial analyses incorporating rudimentary techniques are essential to understand container transportation. Most transportation datasets are offered as raw disjoint data containing dissimilar attributes from different sources making them difficult to fathom any spatial linkages. Route optimization and market accessibility are increasingly becoming important and significant as newer container decongestion methods are put in place. Origin-Destination dichotomies can best be harnessed in the United States by optimizing routes based on available databases. In this study, the Public Use Waybill sample database from Surface Transporation Board were used as preliminary inputs for inland railway route optimization. The paper utilized an approach akin to one used in riverine management to optimize container routes. From the primer databases, in as much as most import containers originate from Asia and Europe and shipped to the U.S. through specific North American ports, a significant portion gets to inland markets through Pacific coast in the U.S. The main hub ports for import containers are Los Angeles/Long Beach and Seattle for transpacific trade and New York/New Jersey and Savannah for transatlantic trade. An anomalous and notably high volume flow can be observed between the Pacific coast and the Mississippi valley area including metropolitan areas like Minneapolis, Chicago, Kansas City, Memphis, Dallas, and Houston. Assessing movement in the Midwest to east U.S., most container traffic volume passes through New York/New Jersey and Norfolk to end in Chicago. It can thus be surmised that an in-depth preliminary assessment of container routing can provide a parametric basis for higher-level cost and multi-modal analyses.

An application of conjoint analysis to explore user perceptions on management information systems

Purpose - – This paper aims to investigate user preferences for the information systems in order to achieve user satisfaction by using conjoint analysis. Design/methodology/approach - – Conjoint analysis is applied for the measurement of user preferences on information systems by seven properties and three levels for each property. To apply the approach, two surveys were designed: the first survey investigates the main properties affecting the end-users satisfaction for using the current information systems based upon literature review and expert interview in Phase I. The second survey weighed the preferences by the virtual profiles of the information systems, which represent the ideal systems. Findings - – The results show that speed-related properties are critical to achieve the end-user satisfaction. The next important property group is related to the access control and system integration between various business modules. From the measurements, the best system file should be constructed with the highly weighed levels of the key attributes. Research limitations/implications - – The virtual profiles are complex for respondents to understand the attributes and the compounds of the virtual products. Moreover, the respondents were overwhelmed by the number of virtual profiles. The attributes were required to enable communication between researchers and respondents. Practical implications - – Information system designers can achieve user satisfaction by combining the highest utility levels of all attributes. Nonetheless, the trade-offs between attributes and their levels should be considered in order to apply the results to the business, depending on the system environments and business practices, by updating the importance of the determinants regularly. Originality/value - – This study applied the conjoint analysis to information management systems in order to design and maintain user satisfaction for the targeted company. This paper will provide alternative ways for the system engineers and developers of the case company by considering the critical attributes, which will affect both user performance and satisfaction.

Spatial analysis for an intermodal terminal to support agricultural logistics: A case study in the upper great plains

Purpose - – The purpose of this study is to address an importance of an intermodal terminal regarding container drayage trips, which have a major concern for agricultural product exporters in the Upper Great Plains. Thus, this study aims to develop a geospatial model considering travel distance and total logistics costs for determining an alternative intermodal terminal location. Design/methodology/approach - – This paper develops a spatial model integrating integer linear programming to determine an intermodal facility location that minimizes total logistics costs. This research considers travel distance and total logistics costs including highway, rail and transshipment costs. Findings - – The results shows that a Dilworth, Minnesota, terminal reduces vehicle miles of travel on both the highways and rail networks and decreases system-wide total logistics costs compared to the do-nothing scenario while decreasing urban congestion costs in metropolitan areas. Research limitations/implications - – The major contribution of the study is that it provides an integrated tool of spatial and economic analyses to support regional decision-making. The paper will be of interest to regional planners and to those in the private business sectors including farmers and manufacturers. The future study should address demand forecasting on the containerized freight in the region. Originality/value - – The novel approach of this paper is to use a link blocking constraint, considering the directions of the freight flow in a

Average opportunity-based accessibility of public transit systems to grocery stores in small urban areas

Abstract This research studies the accessibility of grocery stores to university students using the public transportation system, drawing from a case study of Fargo, North Dakota. Taking into consideration the combined travel time components of walking, riding, and waiting, this study measures two types of accessibilities: accessibility to reach a particular place and accessibility to reach the bus stop to ride the public transit system. These two accessibilities are interdependent and cannot perform without each other. A new method to calculate the average accessibility measure for the transit routes is proposed. A step-wise case study analysis indicates that one route provides accessibility to a grocery store in eight minutes. This also suggests that the North Dakota State University area has moderate accessibility to grocery stores.