A simulation study of service differentiation for the bandwidth request scheme in fixed IEEE 802.16 network

Various flexible mechanisms related to quality of service (QoS) provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the IEEE 802.16 standards. Among the mechanisms, contention based bandwidth request scheme can be used to indicate bandwidth demands to the base station for the non-real-time polling and best-effort services. These two services are used for most applications with unknown traffic characteristics. Due to the diverse QoS requirements of those applications, service differentiation (SD) is anticipated over the contention based bandwidth request scheme. In this paper we investigate the SD with the bandwidth request scheme by means of assigning different channel access parameters and bandwidth allocation priorities at different packets arrival probability. The effectiveness of the differentiation schemes is evaluated by simulations. It is observed that the initial backoff window can be efficient in SD, and if combined with the bandwidth allocation priority, the SD performances will be better.

An interpretation of the energy variations of dispersion managed solitons in terms of effective average dispersion

We show that the variation in dispersion managed soliton energy that occurs as the amplifier position varies within the dispersion map, for a fixed map strength, can be interpreted using the concept of effective average dispersion. Using this concept we physically explain why the location of the amplifier can produce a greater or lesser energy enhancement factor than the lossless model. © 2001 Elsevier Science B.V. All rights reserved.

What do students really think? Understanding postgraduate students' perception of service quality

This paper explores the components of Service Quality in HE from the Business School Postgraduate student perspective. A six-dimensional scale measuring Service Quality is developed based on focus group and survey data. Our findings highlight that postgraduate students are highly outcome oriented; the award of a reputable degree to gain employment is more important than learning for life. Whilst developing employable graduates, Business Schools must not neglect the core service; teaching & learning. In the long-term this contributes to employability rates and the reputation of institutions. However, as student satisfaction is an increasingly paramount objective, balancing the core service and factors perceived as important by postgraduate students is key.

The impact of service characteristics on the switching costs-customer loyalty link

This research investigates the interrelationship between service characteristics and switching costs and makes two contributions to the service retailing literature: (1) As a means of better understanding the effectiveness of switching costs, the study suggests a two-dimensional typology of switching costs, including internal and external switching costs and (2) it reveals that the effect of these switching costs on customer loyalty is contingent upon four service characteristics (the IHIP characteristics of service). We carried out a meta-analytic review of the literature on the switching costs-customer loyalty link and created a hierarchical linear model using a sample of 1,694 customers from 51 service industries. Results reveal that external switching costs have a stronger average effect on customer loyalty than do internal switching costs. Moreover, we find that IHIP characteristics moderate the links between switching costs and customer loyalty. Thus, the link between external switching costs and customer loyalty is weaker in industries higher in the four service characteristics (as compared to industries lower in these characteristics), while the opposite moderating effect of service characteristics for the internal switching costs-loyalty link is noted. © 2014 New York University.

Quality of Service System Approximation in IP Networks

This paper is sponsored by the Ministry of Education and Research of the Republic of Bulgaria in the framework of project No 105 “Multimedia Packet Switching Networks Planning with Quality of Service and Traffic Management”.

A Framework for Design-Time Testing of Service-Based Applications at BPEL Level

Software applications created on top of the service-oriented architecture (SOA) are increasingly popular but testing them remains a challenge. In this paper a framework named TASSA for testing the functional and non-functional behaviour of service-based applications is presented. The paper focuses on the concept of design time testing, the corresponding testing approach and architectural integration of the consisting TASSA tools. The individual TASSA tools with sample validation scenarios were already presented with a general view of their relation. This paper’s contribution is the structured testing approach, based on the integral use of the tools and their architectural integration. The framework is based on SOA principles and is composable depending on user requirements.

Stability in Terms of Two Measures for Differential Equations with “Maxima”

Атанаска Георгиева, Стела Глухчева, Снежана Христова - Изследвана е устойчивостта на нелинейни диференциални уравнения с “максимуми” по отношение на две мерки. Приложени са две различни мерки за началните условия и за решението. Използван е методът на Разумихин, а също така и методът на сравнението на обикновени скаларни диференциални уравнения. Приложението на получените резултати и достатъчни условия за устойчивост е илюстрирано с пример.

Application of Service-Oriented Architecture in Software Quality Management

ACM Computing Classification System (1998): D.2.5, D.2.9, D.2.11.

Solutions of Fractional Diffusion-Wave Equations in Terms of H-functions

MSC 2010: 35R11, 42A38, 26A33, 33E12

A származtatott termékek árazása és annak problémái az egyensúlyelmélet szempontjából (Pricing of derived products and problems with it in terms of equilibrium theory)

A szerző röviden összefoglalja a származtatott termékek árazásával kapcsolatos legfontosabb ismereteket és problémákat. A derivatív árazás elmélete a piacon levő termékek közötti redundanciát kihasználva próbálja meghatározni az egyes termékek relatív árát. Ezt azonban csak teljes piacon lehet megtenni, és így csak teljes piac esetén lehetséges a hasznossági függvények fogalmát az elméletből és a ráépülő gyakorlatból elhagyni, ezért a kockázatsemleges árazás elve félrevezető. Másképpen fogalmazva: a származtatott termékek elmélete csak azon az áron képes a hasznossági függvény fogalmától megszabadulni, ha a piac szerkezetére a valóságban nem teljesülő megkötéseket tesz. Ennek hangsúlyozása mind a piaci gyakorlatban, mind az oktatásban elengedhetetlen. / === / The author sums up briefly the main aspects and problems to do with the pricing of derived products. The theory of derivative pricing uses the redundancy among products on the market to arrive at relative product prices. But this can be done only on a complete market, so that only with a complete market does it become possible to omit from the theory and the practice built upon it the concept of utility functions, and for that reason the principle of risk-neutral pricing is misleading. To put it another way, the theory of derived products is capable of freeing itself from the concept of utility functions only at a price where in practice it places impossible restrictions on the market structure. This it is essential to emphasize in market practice and in teaching.

A tudásérték meghatározása minőségügyi szempontból, hálózatelemzési módszerekkel (The knowledge value in terms of quality with network analysis methods)

A minőségügy egyik kulcsfeladata, hogy azonosítsa az értékteremtés szempontjából kritikus tényezőket, meghatározza ezek értékét, valamint intézkedjen negatív hatásuk megelőzése és csökkentése érdekében. Az értékteremtés sok esetben folyamatokon keresztül történik, amelyek tevékenységekből, elvégzendő feladatokból állnak. Ezekhez megfelelő munkatársak kellenek, akiknek az egyik legfontosabb jellemzője az általuk birtokolt tudás. Mindezek alapján a feladat-tudás-erőforrás kapcsolatrendszer ismerete és kezelése minőségügyi feladat is. A komplex rendszerek elemzésével foglalkozó hálózatkutatás eszközt biztosíthat ehhez, ezért indokolt a minőségügyi területen történő alkalmazhatóságának vizsgálata. Az alkalmazási lehetőségek rendszerezése érdekében a szerzők kategorizálták a minőségügyi hálózatokat az élek (kapcsolatok) és a csúcsok (hálózati pontok) típusai alapján. Ezt követően definiálták a multimodális (több különböző csúcstípusból álló) tudáshálózatot, amely a feladatokból, az erőforrásokból, a tudáselemekből és a közöttük lévő kapcsolatokból épül fel. A hálózat segítségével kategóriákba sorolták a tudáselemeket, valamint a fokszámok alapján meghatározták értéküket. A multimodális hálózatból képzett tudáselem-hálózatban megadták az összefüggő csoportok jelentését, majd megfogalmaztak egy összefüggést a tudáselem-elvesztés kockázatának meghatározására. _______ The aims of quality management are to identify those factors that have significant influence on value production, qualify or quantify them, and make preventive and corrective actions in order to reduce their negative effects. The core elements of value production are processes and tasks, along with workforce having the necessary knowledge to work. For that reason the task-resource-knowledge structure is pertinent to quality management. Network science provides methods to analyze complex systems; therefore it seems reasonable to study the use of tools of network analysis in association with quality management issues. First of all the authors categorized quality networks according to the types of nodes (vertices) and links (edges or arcs). Focusing on knowledge management, they defined the multimodal knowledge network, consisting of tasks, resources, knowledge items and their interconnections. Based on their degree, network nodes can be categorized and their value can be quantified. Derived from the multimodal network knowledge-item network is to be created, where the meaning of cohesive subgroups is defined. Eventually they proposed a formula for determining the risk of knowledge loss.

Economic reform, allocative effiency and terms of trade

It has widely been agreed that the distorted price system is one of the causes of inefficient ecooomic decisions in centrally planned economies. The paper investigates the possible effect of a price reform on the allocation of resources in a situation where micro-efficiency remains unchanged. Foreign trade and endogenously induced terms-of-trade changes are focal points ín the multisectoral applied general equilibrium analysis. Special attention is paid to some methodological problems connected to the representation of foreign trade in such models. The adoption of Armington's assumption leads to an export demand function and this in turn gives rise to the question of optimal export structure, different from the equilibrium one-an aspect so far neglected in the related literature. The results show, that the applied model allows for a more flexible handling of the overspecialization problem, than the linear programming models. It also becomes evident that the use of export demand functions brings unwanted terms-of-trade changes into the model, to be avoided by a suitable reformulation of the model. The analysis also suggests, that a price reform alone does not significantly increase global economic efficiency. Thus the effect of an economic reform on micro-efficiency appears to be a more crucial factor. The author raises in conclusion some rather general questions related to the foreign trade practice of small open economies.

3D TerraFly: Quality of service management for online interactive 3D geographic information system

3D geographic information system (GIS) is data and computation intensive in nature. Internet users are usually equipped with low-end personal computers and network connections of limited bandwidth. Data reduction and performance optimization techniques are of critical importance in quality of service (QoS) management for online 3D GIS. In this research, QoS management issues regarding distributed 3D GIS presentation were studied to develop 3D TerraFly, an interactive 3D GIS that supports high quality online terrain visualization and navigation. ^ To tackle the QoS management challenges, multi-resolution rendering model, adaptive level of detail (LOD) control and mesh simplification algorithms were proposed to effectively reduce the terrain model complexity. The rendering model is adaptively decomposed into sub-regions of up-to-three detail levels according to viewing distance and other dynamic quality measurements. The mesh simplification algorithm was designed as a hybrid algorithm that combines edge straightening and quad-tree compression to reduce the mesh complexity by removing geometrically redundant vertices. The main advantage of this mesh simplification algorithm is that grid mesh can be directly processed in parallel without triangulation overhead. Algorithms facilitating remote accessing and distributed processing of volumetric GIS data, such as data replication, directory service, request scheduling, predictive data retrieving and caching were also proposed. ^ A prototype of the proposed 3D TerraFly implemented in this research demonstrates the effectiveness of our proposed QoS management framework in handling interactive online 3D GIS. The system implementation details and future directions of this research are also addressed in this thesis. ^

Best practices in exemplary service delivery: A multiple case study of service quality

The purpose of this study was to explain how exemplary service providers in luxury hotels provide consistently excellent service. Using a case study framework, the study investigated the service provider's strategies and concepts of service delivery, the importance and implementation of organizational and individual controls, and the role of training and learning. The study identified barriers to service provision and characteristics of the exemplary individuals that affect their ability to deliver luxury service. This study sought to better understand how exemplary service providers learn, think about, and do their work. The sample population of three Five-Diamond-Award winning resorts was selected for their potential for learning about the phenomenon of interest. The results demonstrate that exemplary service providers possess individual characteristics that are enhanced by the organizations for which they work. Exemplary service providers are often exemplary communicators who are emotionally generous and genuinely enjoy helping and serving others. Exemplary service organizations treat their employees as they treat their customers, as suggested by the Service-Profit Chain (Heskett, Sasser & Schlesinger, 1997). Further, they have systems and standards to guarantee satisfactory service experiences for every guest. They also encourage their service providers to personalize their service delivery and to seek opportunities to delight their guests, using a combination of controls, traditions and cultural values. Several customer service theories are discussed in relationship to whether they were or were not supported by the data. The study concluded that the delivery of exemplary service is a complex phenomenon that requires successful interactions between guests, service providers and the organization. A Model of Exemplary Service Delivery is presented and discussed that demonstrates the components of service quality as shown in the data. The model can be used by practitioners seeking to create, enhance, or evaluate their service quality, and by researchers seeking insights into the complex concepts in service quality research. Implications for future research are discussed.