Data from rating scale assessments have rank-invariant properties only, which means that the data represent an ordering, but lack of standardized magnitude, inter-categorical distances, and linearity. Even though the judgments often are coded by natural numbers they are not really metric. The aim of this thesis is to further develop the nonparametric rank-based Svensson methods for paired ordinal data that are based on the rank-invariant properties only. The thesis consists of five papers. In Paper I the asymptotic properties of the measure of systematic disagreement in paired ordinal data, the Relative Position (RP), and the difference in RP between groups were studied. Based on the findings of asymptotic normality, two tests for analyses of change within group and between groups were proposed. In Paper II the asymptotic properties of rank-based measures, e.g. the Svensson’s measures of systematic disagreement and of additional individual variability were discussed, and a numerical method for approximation was suggested. In Paper III the asymptotic properties of the measures for paired ordinal data, discussed in Paper II, were verified by simulations. Furthermore, the Spearman rank-order correlation coefficient (rs) and the Svensson’s augmented rank-order agreement coefficient (ra) were compared. By demonstrating how they differ and why they differ, it is emphasized that they measure different things. In Paper IV the proposed test in Paper I for comparing two groups of systematic changes in paired ordinal data was compared with other nonparametric tests for group changes, both regarding different approaches of categorising changes. The simulation reveals that the proposed test works better for small and unbalanced samples. Paper V demonstrates that rank invariant approaches can also be used in analysis of ordinal data from multi-item scales, which is an appealing and appropriate alternative to calculating sum scores.

Increased product proliferation and global competition are forcing companies within the supply chain to adopt new strategies. Postponement is an effective strategy that allows companies to be agile and cost effective in dealing with the dynamics of global supply chains. Postponement centres around delaying activities in the supply chain until real information about the market is available, which reduces the complexity and uncertainty of dealing with a proliferation of products. A two-echelon divergent supply chain entailing a central production facility and N retailers facing stochastic demand is studied within the inventory-distribution system. A periodic review order-up-to strategy is incorporated at all echelons. Unique to the study, five different systems are created and the effectiveness of several postponement strategies (form and transshipment) under various operational settings are compared. The importance of postponement under an integrated supply chain context and its contribution to various sector implementations are also discussed. Simulation is used to analyze the performance of the systems especially with respect to cost, order lead time and the effectiveness of transshipment policies. The study is unique in determining factors that favour one system implementation over another and distinguishing sector requirements that support postponement. In the study, postponement is found to be an effective strategy in dealing with managing item variety, demand uncertainty and differences in review periods in the two echelon supply chain for different experimental settings.

In this dissertation, we consider a multi-item two-echelon inventory distribution system in which the central warehouse operates with (Q, R) policy, and each local warehouse implements base-stock policy. The objective is to find the policy parameters minimizing the relevant system-wide costs subject to an aggregate mean response time constraint at each facility. We first propose an exact solution procedure based on a branch-and-price algorithm to find the relevant policy parameters of the system considered. Then, we propose four alternative heuristics to find the optimal or near-optimal policy parameters of large practical-size systems. The first heuristic, which we call the Lagrangian heuristic, is based on the simultaneous approach and relies on the integration of a column generation method and a greedy algorithm. The other three heuristics are based on the sequential approach, in which first the order quantities are determined using a batch size heuristic, then the reorder levels at the central warehouse and the basestock levels at the local warehouses are determined through the same method used for the Lagrangian heuristic. We also propose a lower bound for the system-wide cost. Later, we extend our study to compound Poisson demand. The performance of the Lagrangian heuristic is found to be extremely well and improves even further as the number of parts increases. Also the computational requirement of the heuristic is quite tolerable. This makes the heuristic very promising for large practical industry-size problems. The performance of the sequential heuristics is also satisfactory, but not as much as the Lagrangian heuristic.

In this study, inventory&ndash / distribution system of a company operating in Fast Moving Consumer Goods (FMCG) industry is analyzed. The system is a multi&ndash / item, two-echelon, divergent inventory&ndash / distribution system with transportation constraints. The warehouses in the system are nonidentical and all of the warehouses are allowed to hold stock. The goal is to achive target customer service levels. Throughout the system, inventory is controlled by echelon stock periodic review (R, S) order-up-to level policy. The problem is the determination of inventory control parameters in the system and effective replenishment of the inventories of many items at regional warehouses under transportation constraints. An approach consisting of three modules operating in a hierarchy is developed to manage the system. The approach calculates the inventory control parameters of the items (order-up-to levels at the regional warehouses and stock allocation fractions) / determines the replenishment periods of the items with the objective of balancing the vehicle requirements among periods and performs the daily replenishment of inventories minimizing the maximum deviation from the inventory policy under transportation constraints. A heuristic approach is adapted from the literature for the inventory control parameter determination part of the approach / an IP model is formulated for the replenishment period scheduling part and a MIP model is constructed for the replenishment process. The proposed approach is simulated with retrospective data of the company and compared with the existing system in the company, in terms of the performance measures defined. Satisfactory results are obtained with the proposed system.

Undoubtedly one of the most significant developments to affect marketing worldwide in the 21st century has been the development of the Internet. As a communication tool the Internet is emerging as a new challenge to mass media advertising. As a result advertising agencies need to readdress their techniques, services and agency structure. Additionally, the shape and form of the traditional advertising agency will need to change along with the adoption and usage of this new interactive media channel. Agencies are now being forced to consider broadening their service offerings to clients. Apart from widening their service offerings, advertising agencies are being driven to invest in building and sustaining valuable client relationships to establish client loyalty, with profit and a healthy bottom-line being the ultimate objectives. Bush, Bush and Harris (1998) point out however, that whilst a growing number of companies are interested in developing an online presence, significant confusion remains about what this new medium will offer stakeholders in the advertising industry. The study undertaken in this thesis explores the relationship between two influential stakeholders in the advertising industry - advertising agencies and their clients. To explore this relationship, the study modified Parasuraman, Zeithamal and Berry's (1988) SERVQUAL model to explore whether gaps exist between agency-client expectations of the value of the Internet as a promotional tool. The SERVQUAL model, which was designed for measuring gaps between service expectations and perceptions, was adapted for use in the business-to-business environment (B2B). In the marketing literature there is little evidence of B2B research in relation to agency-client relationships, nor has there been significant scholarly work exploring the effect of the introduction of the Internet as a promotional tool on the agency-client relationship. The research undertaken in this study aims to respond to this gap in the marketing literature by addressing the broad research question: &quotHow will the introduction of the Internet as a promotional tool impact agency-client relationships?" Undertaking a review of agency-client expectations of the value of the Internet will ascertain whether gaps exist between agency and client expectations of the value of the Internet as a promotional tool. The discovery of gaps in the agency-client relationship in relation to Internet perceptions will indicate potential opportunities and challenges that need to be addressed by advertising agencies interested in extending their advertising services to embrace the Internet as a promotional tool. A major assumption in this inquiry was that gaps would exist between agency and client perceptions of Internet value. In particular, that advertising agencies would perceive the Internet to be a more valuable promotional tool than their clients. This assumption was informed from mass media and industry press, which indicated that advertising agencies were embracing new advertising creative in website design and strategic marketing activities using interactive media such as newsgroups and email to reach customers. However, the research of Bush et al. (1998) and Ducoffe (1996) suggests that little is known about the value of these Internet-based activities. Such thinking raises questions, such as: are advertisers feeling compelled to jump on the Internet bandwagon because of its popularity, or are businesses' desires to use Internet advertising a manifestation of Internet hype? To begin to answer these questions advertising industry stakeholders need to identify whether gaps do exist between agency and client perceptions of the value of the Internet as a promotional tool. The existence of such gaps could lead to tension in the agency-client relationship, which may ultimately mean a loss of client accounts for the advertising agency. Identifying and remedying such gaps could therefore aid in ensuring long-term and profitable working relationships with the agency's clients. To undertake this advertising industry research and respond to the research questions in this study an international advertising agency network, made up of 206 offices in 90 countries and a selection of their clients, were recruited to participate in the study. A two stage survey method approach was adopted because it was a time-efficient and affordable method for collecting detailed information from a dispersed network of professionals. The survey tool was a web-based questionnaire which was firstly submitted to a selection of advertising agencies within the international agency network. On completion of the questionnaire, agencies were asked to provide contact details for their top three billing clients. The second stage of the survey research involved the submission of a client questionnaire to the client contacts provided by the advertising agency. Both questionnaires used a modified SERVQUAL multi-item scale to measure service expectations. Discrete agency and client questions were also included in the respective questionnaires to situate the SERVQUAL analysis within the context of Internet usage, value perceptions and organisational characteristics (e.g. agency size, advertising spend, experience in using interactive media). The major finding of this study is that within the international advertising agency network there were no significant gaps in agency-client expectations concerning the value of the Internet as a promotional tool. Whilst several statistical analyses were undertaken, including bivariate and multivariate techniques such as Pearson's Chi-Square cross-tabulations, independent t-tests and ANOVAs, no statistically significant results are reported. In fact, it was found that advertising agencies and clients have similar expectations of the value of the Internet as a promotional tool. Gaps actually exist in relation to the clients who use the Internet as a promotional tool and agencies who supply Internet advertising services. Many agencies within this international agency network were found to be actively using the Internet, but their Internet advertising functions were not being provided by their traditional advertising agency. Descriptive analyses reported in the findings from this research study indicate that advertising agencies in this international network need to better understand their clients' Internet promotion needs. This will ensure the establishment of healthy, profitable and long-term agency-client relationships in the future. The research findings from this study offer advertising agencies worldwide insight into client expectations of the Internet, as well as other agency services. Furthermore, the findings reported contribute to the current small body of research in relation to B2B relationships in the advertising industry. The groundwork is set for future analysis of agency-client relationships in the advertising industry. In summary, while gaps between agency and client expectations of the value of the Internet as a promotional tool were expected, this research study found that agency and client expectations are quite similar. Analysis did reveal that one important factor, which influences the agency-client relationship, relates to the provision of Internet advertising services. Specifically, when an agency is not responsible for developing and maintaining clients' Internet advertising, these clients are utilising services from external providers of Internet services. These new stakeholders, who provide specialist services (i.e. graphic design houses, Internet advertising specialists and client's in-house Internet services), are changing the competitive environment of advertising services in the industry. Another interesting discovery, specific to the sample population, was that one third of agencies within the study did not provide Internet advertising services to current clients. However, these agencies have clients that use Internet advertising. On the one hand, this finding indicates that opportunities exist for these agencies to extend their service portfolio to embrace Internet advertising. However, it also raises an important question: that is, have these agencies created greater competition by not providing a full service communication portfolio for clients? These factors, and other methodological issues will inform directions for future research to explain the influential role of the Internet within the agency-client relationship in the advertising industry.

This dissertation is concerned with decision making in retail operations management. Specifically, we focus on pricing, variety, and inventory decisions, which are at the interface of the marketing and operations functions of a retail firm. We consider two problems that relate to two major types of retail goods. First, we study joint pricing, variety, and inventory decisions for a set of substitutable" items that serve the same need for the consumer (commonly referred to as a "retailer's product line"). Second, we present a novel model of a selling strategy for "complementary" items that we refer to as ``convenience tying," and focus on analyzing the effect of this selling strategy on pricing and profitability. We also study inventory decisions under convenience tying and exogenous pricing. For a product line of substitutable items, the retailer's objective is to jointly determine the set of variants to include in her product line ("assortment"), together with their prices and inventory levels, so as to maximize her expected profit. We model the consumer choice process using a multinomial logit choice model and consider a newsvendor type inventory setting. We derive the structure of the optimal assortment for a special case where the non-ascending order of items in mean consumer valuation and the non-descending order of items in unit cost agree. For this special case, we find that an optimal assortment has a limited number of items with the largest values of the mean consumer valuation (equivalently, the items with the smallest values of the unit cost). For the general case, we propose a dominance rule that significantly reduces the number of different subsets to be considered when searching for an optimal assortment. We also present bounds on the optimal prices that can be obtained by solving single variable equations. Finally, we combine several observations from our analytical and numerical study to develop an efficient heuristic procedure, which is shown to perform well on many numerical tests. With the objective of gaining further insights into the structure of the retailer's optimal decisions, we study a special case of the product line problem with "similar items" having equal unit costs and identical reservation price distributions. We also assume that all items in a product line are sold at the same price. We focus on two situations: (i) the assortment size is exogenously fixed, while the retailer jointly determines the pricing and inventory levels of items in her product line; and (ii) the pricing is exogenously set, while the retailer jointly determines the assortment size and inventory levels. We also briefly discuss the joint pricing/variety/inventory problem where the pricing, assortment size, and inventory levels are all decision variables. In the first setting, we characterize the structure of the retailer's optimal pricing and inventory decisions. We then study the effect of limited inventory on the optimal pricing by comparing our results (in the ``risky case" with limited inventory) with the ``riskless case," which assumes infinite inventory levels. In addition, we gain insights on how the optimal price changes with product line variety as well as demand and cost parameters, and show that the behavior of the optimal price in the risky case can be quite different from that in the riskless case. In the second setting, we characterize the retailer's optimal assortment size considering the trade-off between sales revenue and inventory costs. Our stylized model allows us to obtain strong structural and monotonicity results. In particular, we find that the expected profit at optimal inventory levels is unimodal in the assortment size, which implies that the optimal assortment size is finite. By comparison to the riskless case, we find that this finite variety level is due to inventory costs. Finally, for the joint pricing/variety/inventory problem, we find that even when the retailer has control over the price, finite inventories still restrict the variety level. We also propose several bounds that can be useful in solving the joint problem. We then study a convenience tying strategy for two complementary items that we denote by "primary" and "secondary." The retailer sells the primary item in an appropriate department of her store. In addition, to stimulate demand, the secondary item is offered in two locations: its appropriate department and the primary item's department where it is displayed in very close proximity to the primary item. We analyze the profitability of this selling practice by comparing it to the traditional independent components strategy, where the two items are sold independently (each in its own department). We focus on understanding the effect of convenience tying on pricing. We also briefly discuss inventory considerations. First, assuming infinite inventory levels, we show that convenience tying decreases the price of the primary item and adjusts the price of the secondary item up or down depending on its popularity in the primary item's department. We also derive several structural and monotonicity properties of the optimal prices, and provide sufficient conditions for the profitability of convenience tying. Then, under exogenous pricing, we find that convenience tying is profitable only if it generates enough demand to cover the increase in inventory costs due to decentralizing the sales of the secondary item. / Ph. D.

The most costly and labor-intensive activity for almost every warehouse is the order picking process and a key challenge for manufacturing companies is to store parts in an efficient way. Therefore, to minimize the order retrieval time when picking from a storage, the need of a sufficient storage categorization strategy becomes vital. One of the logistics centers at Scania in Södertälje stores parts that will be transported to the chassis assembly and the assembly of gearboxes and axles when needed in the production. In one of the storage areas at the logistics center, namely the PS storage, the forklift drivers picking from the storage have experienced congestion in the storage aisles and that it might be possible to reduce the order fulfillment time when picking the orders. This master thesis aims to investigate the possibility of optimizing the picking process in the PS storage, with respect to the order fulfillment time for the forklift drivers, with categorization of the goods. This has been analyzed with a heuristic optimization approach and with the use of a discrete event simulation model, where different categorization strategies have been applied on the storage and compared to the current state. By categorizing the goods in the PS storage, a reduction of the order fulfillment time can be done of around 4% - 5% compared to the current state with all tested categorization strategies. The strategy which has been shown to give the largest improvement is by categorizing the parts in the storage according to their final delivery address at the production line, which would reduce the order fulfillment time by 5.03% compared to the current state. With this categorization method, parts that are picked on the same route are located close to each other.

Social ångest beskrivs som en obehagskänsla kopplat till sociala situationer där individen upplever en risk att bli negativt bedömd av andra (APA, 2013).Det finns ett stort behov av att effektivisera mätning av social ångest samt att på ett precist sätt mäta dess symtom. Vidare råder det svårigheter att mäta psykologiska konstrukt på ett tillförlitligt sätt. Borg centiMaxskalan® (CR100) är en skattningsskala som utvecklats för att mäta subjektiva upplevelser med större precision. Syftet med denna studieär att studera begreppsvaliditeten för single-item -mätning av social ångest med Borg centiMaxskalan®samt att se om single-item-mätning mäter social ångest på ett likvärdigt sätt som ett multi-item. För att undersöka detta jämförs single-item-mätning med centiMax för social ångest (SÅ-SI-cM) mot SPIN och socialångestskalan med centiMax (SÅS-MI-cM). Data samlades in digitalt via ett bekvämlighetsurval (N = 382). Resultatet visar ett positivt samband mellan SPIN och single-item-mätning med centiMax för social ångest(r = .77, p <.001) samt ett positivt samband mellan single-item-mätning med centiMax och multi-item-mätning med SÅS-cMax (r = .77, p <.001). Sammanfattningsvis tyder resultatet på att single-item-mätning med centiMaxmäter social ångest på ett likvärdigt sätt som SPIN och SÅS-MI-cM.Resultatet i denna studie indikerar på att vidare studier med single-item-mätningav social ångest med centiMax (SÅ-SI-cM) är av intresseför att vidare validera detta mätinstrument

No description available.

Shipment Consolidation (SCL) is a logistics strategy that combines two or more orders or shipments so that a larger quantity can be dispatched on the same vehicle to the same market region. This dissertation aims to emphasize the importance and substantial cost saving opportunities that come with SCL in a logistics supply chain, by offering new models or by improving on the current body of literature. Our research revolves around "three main axes" in SCL: Single-Item Shipment Consolidation (SISCL), Multi-Item Shipment Consolidation (MISCL), and Pricing and Shipment Consolidation. We investigate those topics by employing various Operations Research concepts or techniques such as renewal theory, dynamic optimization, and simulation. In SISCL, we focus on analytical models, when the orders arrive randomly. First, we examine the conditions under which an SCL program enables positive savings. Then, in addition to the current SCL policies used in practice and studied in the literature, i.e. Quantity-Policy (Q-P), Time-Policy (T-P) and Hybrid Policy (H-P), we introduce a new one that we call the Controlled Dispatch Policy (CD-P). Moreover, we provide a cost-based comparison of those policies. We show that the Q-P yields the lowest cost per order amongst the others, yet with the highest randomness in dispatch times. On the other hand, we also show that, between the service-level dependent policies (i.e. the CD-P, H-P and T-P), H-P provides the lowest cost per order, while CD-P turns out to be more flexible and responsive to dispatch times, again with a lower cost than the T-P. In MISCL, we construct dispatch decision rules. We employ a myopic analysis, and show that it is optimal, when costs and the order-arrival processes are dependent on the type of items. In a dynamic setting, we apply the concept of time-varying probability to integrate the dispatching and load planning decisions. For the most common dispatch objectives such as cost per order, cost per unit time or cost per unit weight, we use simulation and observe that the variabilities in both cost and the optimal consolidation cycle are smaller for the objective of cost per unit weight. Finally on our third axis, we study the joint optimization of pricing and time-based SCL policy. We do this for a price- and time-sensitive logistics market, both for common carriage (transport by a public, for-hire trucking company) and private carriage (employing one's own fleet of trucks). The main motivation for introducing pricing in SCL decisions stems from the fact that transportation is a service, and naturally demand is affected by price. Suitable pricing decisions may influence the order-arrival rates, enabling extra savings. Those savings emanate from two sources: Scale economies (in private carriage) or discount economies (in common carriage) that come with SCL, and additional revenue generated by employing an appropriate pricing scheme. Throughout the dissertation, we offer numerical examples and as many managerial insights as possible. Suggestions for future research are offered.