Taesik Lee

Gender differences in consumers' perception of online consumer reviews

Since the early days of the Internet, gender gap has existed in using the Internet, and it is particularly evident for online shopping. Females perceive higher level of risk for online shopping, and as a result, they tend to hesitate to make purchase online. Online consumer reviews can effectively mitigate such perceived risk by females and thereby attract them to buy online. This study investigates the effect of online consumer reviews on consumer’s purchase intention. In particular, we examine whether there are gender differences in responding to online consumer reviews. The results show that the effect of online consumer reviews on purchase intention is stronger for females than males. The negativity effect, that consumers are influenced by a negative review more than by a positive review, is also found to be more evident for females. These findings have practical implications for online sellers to guide them to effectively use online consumer reviews to engage females in online shopping.

Untangling the antecedents of initial trust in Web-based health information: The roles of argument quality, source expertise, and user perceptions of information quality and risk

As the Internet develops as a medium for disseminating health-related information, research on Web-based health information consumption grows increasingly important to academics and practitioners. Building on the current research in this area, our study proposes a model of initial trust formation in Web-based health information, rooted in the elaboration likelihood model (ELM) and Toulmins model of argumentation. The proposed model theorizes trust as a function of perceived information quality and perceived risk, which are in turn determined by the structural quality of the message (argument quality) and the expertise of the message source (source expertise). Testing of the research model was accomplished via a field experiment involving 300 online users who had searched for health information on the Web. Overall, the results largely support the proposed model, explaining substantial variance in trust and highlighting the important but distinct roles that argument quality, source expertise, and user perceptions of information quality and risk play in determining an individuals decision to trust health information online.

Product type and consumers’ perception of online consumer reviews

Consumers hesitate to buy experience products online because it is hard to get enough information about experience products via the Internet. Online consumer reviews may change that, as they offer consumers indirect experiences about dominant attributes of experience products, transforming them into search products. When consumers are exposed to an online consumer review, it should be noted that there are different kinds of review sources. This study investigates the effects of review source and product type on consumers’ perception of a review. The result of the online experiment suggests that product type can moderate consumers’ perceived credibility of a review from different review sources, and the major findings are: (1) consumers are more influenced by a review for an experience product than for a search product when the review comes from consumer-developed review sites, and (2) a review from an online community is perceived to be the most credible for consumers seeking information about an experience product. The findings provide managerial implications for marketers as to how they can better manage online consumer reviews.

Reducing emergency department overcrowding: five patient buffer concepts in comparison

Emergency Department (ED) overcrowding is a common medical care issue in the United States and other developed nations. One major cause of ED crowding are holding patients waiting in the Emergency Room (ER) for inpatient unit admission where they block critical ED resources. With input data from a hospital in Massachusetts/USA, we tested five patient buffer concepts which aim at relieving pressure of the ER. The buffers are also assumed to improve patient and staff satisfaction through their design tailored to needs in patient flow. To ensure patients safety, we performed tests with discrete event simulation in which we discovered `triage to bed time¿ reductions of up to 22% and `diversion hour¿ decreases of up to 24%. All buffers managed to run with significantly less resources than the ER. Our findings have a potential impact on hospital process flow due to clear results which offer substantial improvement of hospital organization.

Optimal allocation of emergency medical resources in a mass casualty incident: Patient prioritization by column generation

Mass casualty incidents create a surge in demand for emergency medical services, and this can often overwhelm the emergency response capacity. Thus, it is critically important to ration the emergency medical resources based on prioritization to maximize the lifesaving capacity. In a traditional triage scenario, the priority for receiving care is solely determined by a patient’s criticality at the time of assessment. Recent studies show that a resource-constrained triage is more effective in providing the greatest good to the maximum number of patients. We model this problem as an ambulance routing problem, and determine the order and destination hospitals for patient evacuation. This is formulated as a set partitioning problem, and we apply a column generation approach to efficiently handle a large number of feasible ambulance schedules. We show that the proposed algorithm with a column generation approach solves the problem to near optimality within a short computation time, and the solutions derived by the algorithm outperform fixed-priority resource allocations.

Simultaneous Location of Trauma Centers and Helicopters for Emergency Medical Service Planning

This paper studies the problem of simultaneously locating trauma centers and helicopters. The standard approach to locating helicopters involves the use of helicopter busy fractions to model the random availability of helicopters. However, busy fractions cannot be estimated a priori in our problem because the demand for each helicopter cannot be determined until the trauma center locations are selected. To overcome this challenge, we endogenize the computation of busy fractions within an optimization problem. The resulting formulation has nonconvex bilinear terms in the objective, for which we develop an integrated method that iteratively solves a sequence of problem relaxations and restrictions. Specifically, we devise a specialized algorithm, called the shifting quadratic envelopes algorithm, that 1 generates tighter outer approximations than linear McCormick envelopes and 2 outperforms a Benders-like cut generation scheme. We apply our integrated method to the design of a nationwide trauma care system in Korea. By running a trace-based simulation on a full year of patient data, we find that the solutions generated by our model outperform several benchmark heuristics by up to 20%, as measured by an industry-standard metric: the proportion of patients successfully transported to a care facility within one hour. Our results have helped the Korean government to plan its nationwide trauma care system. More generally, our method can be applied to a class of optimization problems that aim to find the locations of both fixed and mobile servers when service needs to be carried out within a certain time threshold.

Axiomatic Design for eco-design: eAD+

The majority of the ecological effects of a company and its products are determined in the early stages of design. Since Axiomatic Design (AD) may be helpful in guiding early design decisions, we develop an eco-design methodology based on AD called eAD+. We identify hundreds of factors that are relevant for eco-design from stakeholders, the literature and company websites. These are condensed into 94 ecological customer needs (eCNs). From these we identify about 20 ecological functional requirements (eFRs) that can be used at the enterprise and product/system level. We next consider how the eCNs, eFRs and ecological metrics such as life cycle assessment (LCA) can be included in AD. To avoid issues related to functional independence, which is essential in AD, we consider LCA as a selection criterion. LCA can be naturally included in the AD design matrix by appending additional rows but not additional columns. Several examples using eAD+ are considered to demonstrate how decoupling arises in eco-design and how to include LCA. It is our hope that these steps towards a general extension of AD for eco-design will help designers seeking to improve the ecological performance of their company and the products/systems it provides.

A simulation-based iterative method for a trauma center: air ambulance location problem

Timely transport of a patient to a capable medical facility is a key factor in providing quality care for trauma patients. This paper presents a mathematical model and a related solution method to search for optimal locations of trauma centers and air ambulances. The complicatedness of this problem stems from the characteristic that optimal locations for the two resources are coupled with each other. Specifically, this coupling makes it difficult to develop a priori estimates for the air ambulances busy fraction, which are required to construct a probabilistic location model. We propose a method that uses integer programming and simulation to iteratively update busy fraction parameters in the model. Experimental results show that the proposed method is valid and improves the solution quality compared to alternative methods. We use real data on Korean trauma cases, and apply the method to the design of a trauma care system in Korea.

Outpatients appointment scheduling with multi-doctor sharing resources

In an outpatient department of general hospitals, several doctors practice simultaneously. While individual doctors have their own patient panel and work independently, they share common resources such as space, personnel and equipments. In such settings, designing an optimal scheme to manage patient flow, e.g. appointment scheduling, requires to consider patient flows for all doctors instead of focusing on a single doctor. This paper examines an appointment scheduling problem for an outpatient unit where multiple doctors practice independently yet sharing common resources. An ophthalmology department of a large-scale general hospital in Korea is modeled in discrete event simulation. Our experimental results show that under multiple-doctor and resource-sharing environment, collection of the seemingly optimal appointment rules for individual doctors does not lead to optimal performance for the system. It implies that altering a patient flow, especially modifying the scheduling rule, should consider the interdependence effects within the system.

Group Decision Procedure to Model the Dependency Structure of Complex Systems: Framework and Case Study for Critical Infrastructures

This paper proposes a group decision framework to model the dependency structure of a complex system based on expert surveys. The proposed framework is designed to systematically populate a dependency matrix whose entry indicates the degree that its row element is influenced by its column element. The degree of dependency is assessed based on two different perspectives-of the influencing element and of the influenced element-and the assessments with the two perspectives are separately compiled and compared in the initial round survey. Entries with large assessment gaps are classified as discussion items and a group decision procedure to reduce the gaps in these items is applied in the consensus round survey. A case study for dependency modeling of critical infrastructures of South Korea was conducted using the proposed framework and its effectiveness was demonstrated. The analysis on the results of the case study discovered an insight that the opinions from the influenced elements are more convincing and respected in the consensus round than those from the influencing elements.