Thesis (M.H.S.A.)--University of Michigan, 1977.

Thesis (M.H.S.A.)--University of Michigan, 1977.

Never had consumers been empowered by information technologies such as social media-enabled portals that permit them to access and conduct all aspects of life and work activities through a mobile phone at any time from anywhere. WeChat, with over 963 million active monthly users, represents such a revolutionary platform. In healthcare, patients can use WeChat to make doctor appointments, access health and lab results, consult with doctors, and check on the queuing status and parking conditions in the health clinics and hospitals. Such social-media-enabled systems have transformed the relationships between consumers and businesses into a new paradigm in which the supply-side is driven by the demand-side. As a result, the new technology is fundamentally changing; not only the context in which business is conducted but also the business itself. The extant literature on technology acceptance, however, has mostly focused on technical functionalities and user characteristics without adequately considering the specific context in which the technology is used. Although these affordance concepts have advanced our knowledge about the interactions between technology and users, the specific contexts in which such interactions occur have been largely ignored. There is a critical literature gap that hinders our ability to understand and provide guidelines to help organizations deal with the complex challenges they face in managing social mediaenabled technologies in today’s changing environment. Our research attempts to bridge this critical literature gap by conceptualizing the concept of contextual affordance, and by examining its determinants and consequences in healthcare services. We use a combination of qualitative method and quantitative method. Research sites are in China across multiple healthcare facilities. The anticipated findings include validated dimensions of contextual affordance and relationships between contextual affordance and its determinants and impacts on clinical process changes and health service outcomes. Theoretically, this study extends the current understanding of affordance by considering contextual dimensions of affordance, and by examining the relationships between contextual affordance and its determinants and consequences. Practically, this study sheds new lights on how organizations should go beyond the out-of-context interactions between technologies and users by considering users’ perceived affordance of technology within the specific contexts of use.

<p>A polling system is a cyclic queueing model with multiple customer classes and a single server. Each customer class has its own queue (station). After the server switches to a station, it serves customers waiting at that station according to a specified service regime, e.g., exhaustive, gated or globally gated. It then moves to the next station, following a strict cyclic order. These models have several application areas including computer and communication networks and multi-item production systems. For example, a Local Area Network (LAN) can be modeled as a polling system by defining the central processing unit as the server and the data transmission requests from each terminal as customers. Similarly, a multi-item production system can be modeled as a polling system by considering the flexible machining cell as the server and each product type as a different customer class. In most systems that polling models are used to represent, the server requires time to switch and/or setup before it may start serving a different customer class. These processes (switching/setup) may take considerable amounts of time, and when that happens, it is undesirable to setup for a product type if there are no (or only a few) jobs of that type in the system. Therefore, a server scheduling policy that ignores system state information can easily lead to suboptimal performance.</p> <p>Whereas most previous studies on polling models have assumed that the server behaves independently of the state of the system, we discuss two kinds of state-dependent server scheduling rules: i) the threshold setups model, and ii) the threshold start-up model. In the former model, the server does not setup (and does not serve any customers) at a station at which it finds less than a critical number of waiting customers, called the setup threshold. In the latter model, the server starts idling each time the system becomes empty, and it stays idle until arrivals to the system reach a critical number, called the start-up threshold. The server then resumes service from the station where it had stopped. Our analysis makes it possible to compare system performance under these state-dependent server scheduling rules and state-independent rules.</p> <p>In this dissertation the following results are achieved. We develop an exact analysis for the one-threshold setup model with two stations, and an efficient approximation for the same model with any number of stations. For the general threshold setups model, we construct a numerical solution technique which is near-exact for calculating queue length distributions and station mean waiting times. The threshold start-up model is analyzed in detail, and mathematically exact expressions for man station waiting times are obtained for both exhaustive and globally gated service regimes. For each model, the extension to the gated service regime is also discussed.</p> / Doctor of Philosophy (PhD)

<p>A value is the concept of the desirable. If those who develop information systems and those who use information systems have different values, the value gap can lead to serious consequences. Two methods are developed and tested in this thesis to measure the value systems of developers, users and other participants in the information system development process: one based on a personal value questionaire (PVQ) and the other based on multi-attribute value theory (MAVT).</p> <p>A framework for information systems (IS) relevant values was developed to enumerate and organize the values to be measured into three groups: economic, technical and socio-political-psychological.</p> <p>There were 86 values enumerated, which were used in the PVQ method to survey 132 system developers and 47 47 system users in 13 firms. Developers and users were found to have similar values with respect to economic and technological items but sharply differing values in the socio-political-psychological group.</p> <p>A condensed set of items consisting of two economic, five technological and four socio-political items, were organized in a hierarchical struture, for the MAVT method. Preference conditions were assessed and values were measured using the rating scale approach. Three subjects were interviewed in depth; two produced additive multi-attribute value functions, while one produced a multiplicative function</p> / Doctor of Philosophy (PhD)

<p>Several methods have been proposed and tested for calculating lower bounds on the objective function of facilities problems. These methods contribute to the efficiency of iterative solution methods by allowing the user to terminate the computation process when the objective function comes within a predetermined fraction of the optimal solution. Two of the existing bounding methods have been presented only for single facility location models with Euclidean (straight-line) distances. One of these methods uses the dual of the single facility location model to compute a lower bound. This thesis introduces a method for generating a feasible dual solution from any primal solution by means of a projection matrix. The projection matrix method is applied to single and multi-facility models. The second bounding method, which involves the solution of a rectilinear distance model to obtain a lower bound, is extended in this thesis to include a generalized, distance function and the multi-facility situation. Computation results for the two new bounding methods are compared with several existing bounding methods. These results should aid practitioners in selecting an appropriate bounding method for an iterative solution method to a facilities location problem.</p> / Doctor of Philosophy (PhD)

<p>In this dissertation, we look at two families of distance predicting functions, the ℓkpθ norm family and the block norm family, that can be used for modelling actual distances. To compare the distance-predicting accuracy of the two families, an empirical study is conducted. Two types of regions, which are large geographic regions and urban centres, are used in the study. In the large geographic regions, actual distances between cities in each region are modelled, whereas in the urban centres, actual distances within a city are modelled. To evaluate the accuracy of the different norms, two goodness-of-fit criteria are employed. For the block norms, new procedures that determine global solutions for the criteria are developed. Normality assumptions regarding the individual terms of the criteria are examined since these terms are used to formulate statistical tests that are sensitive to departures from normality. A new criterion for evaluating the accuracy of a distance predicting function is developed. This criterion, unlike the other two criteria, is impartial both to short actual distances and to long actual distances. The criterion is used to evaluate the accuracy of the ℓkpθ norm for the geographic regions that were used in the empirical study. A statistical analysis of the errors from this new criterion leads to the development of confidence intervals for unknown distances in any geographic region. The results from this thesis will help an analyst select an appropriate distance predicting function to model actual distances in any application. Further, a new measure for evaluating distance predicting functions may be considered by an analyst, and confidence intervals for unknown distances can be easily constructed.</p> / Doctor of Philosophy (PhD)

<p>This thesis deals with game theory and its applications in management science and focuses upon some management science areas such as inventory control and new product development. Some interesting theoretical findings and new policies are obtained by using the game theoretical approach to analyze certain management science problems. The discussion starts with a review of static game theory models and their applications in management science. Of particular interest here is the state of the art of game theory as an analytical technique in management science. Chapters Two and Three discuss the discount problem. Particular attention is paid to the gaming nature and the buyer's demand aspect of the problem. It is shown that, if they work independently and rationally, the seller and the buyer can gain from price discount only if it can attract more demand from the buyer. Nevertheless, they can gain from quantity discount even if demand is constant. Quantity discount is always better than a price discount for the seller and, in certain situations, can be very efficient in obtaining the maximum profit. Optimal decisions are obtained for both the seller and the buyer under various conditions. Chapter Four studies the order quantities of substitutable products with stochastic demands. This analysis extends the newsboy problem analysis into situations with three or more players. It is shown that there is one Nash equilibrium for the problem. If any player(s) acts irrationally, the other players' decision problem reduces to the one without the irrational player(s). If cooperation is possible, their decisions depend on whether side payments are allowed. If side payments are allowed, they will determine their order quantities together. If side payments are not allowed, secure strategies exist for each player. It is also shown that all players' cooperation is often worthwhile and feasible. Chapter Five analyzes the growth of new repeat purchasing products. It is shown that markets of repeat purchasing products will never saturate like that of consumer durable products unless customers are extremely loyal to at least one product. For new repeat purchasing products, the optimal advertising strategy is increasing at the introductory stage and then decreasing or possibly terminating after some time and, the optimal service strategy is monotonically increasing at the introductory stage and then possibly maintained constant at a certain level. Especially, more advertising should be done at early stages against competitors' advertising campaign. The game is solved analytically for optimal strategies in the case where all the control functions representing the effects of advertising and service are linear in the control variables. Finally, the main findings and possible extensions to this research are briefly summarized in Chapter Six. (Abstract shortened by UMI.)</p> / Doctor of Philosophy (PhD)

<p>This thesis represents research in the combined areas of inventory and maintenance. It analyzes two independent inventory and maintenance problems under dynamic systems: (i) a production and maintenance problem and (ii) a repairable-item inventory problem. For each problem, the thesis develops a new control model and proposes a simultaneous determination of optimal inventory and maintenance policies. The first part of the thesis examines a production process where the process performance deteriorates over time in the absence of preventive maintenance. First, it develops a new finite-time control model for optimal production and maintenance decisions by combining a dynamic maintenance model with a production control model. Second, it derives the necessary conditions for optimal production and maintenance controls using the maximum principle. Finally, it proposes two optimization algorithms for numerically solving the necessary conditions already derived. The second part of the thesis considers the repairable-item inventory problem, which may be faced at each period by the inventory manager responsible for determining the optimum quantities to purchase new serviceable units, to repair and to junk returned repairable units in order to satisfy random demand for serviceable units. First, it proposes an inventory model for repairables, incorporating several important features. The model includes a periodic review policy, random demand, lost sales for unsatisfied demand, set-up costs for ordering and repair, and a dynamic return process. Second, it employs a quite different solution methodology from what the previous research has used. The approach employed here is a 'Markov decision process (MDP)'. With this approach, the inventory problem is remodelled as a discrete-time Markov decision problem with two-dimensional state and three-dimensional decision spaces and then solved for finite-time planning horizon using the backward induction algorithm and for infinite-time planning horizon using the method of successive approximations. Finally, it introduces and utilizes two acceleration techniques, the error bounds approach and State Decomposition by Dimension (SDD), for speeding up the convergence of the computational methods described above.</p> / Doctor of Philosophy (PhD)

published_or_final_version / Management Studies / Doctoral / Doctor of Philosophy