The primary research objective of this dissertation is to demonstrate that the effects of communication protocol stack offload (CPSO) on application execution time can be attributed to the following two complementary sources. First, the application-specific computation may be executed concurrently with the asynchronous communication performed by the communication protocol stack offload engine. Second, the protocol stack processing can be accelerated or decelerated by the offload engine. These two types of performance effects can be quantified with the use of the degree of overlapping Do and degree of acceleration Daccs. The composite communication speedup metrics S_comm(Do, Daccs) can be used in order to quantify the combined effects of the protocol stack offload. This dissertation thesis is validated empirically. The degree of overlapping Do, the degree of acceleration Daccs, and the communication speedup Scomm characteristic of the system configurations under test are derived in the course of experiments performed for the system configurations of interest. It is shown that the proposed metrics adequately describe the effects of the protocol stack offload on the application execution time. Additionally, a set of analytical models of the networking subsystem of a PC-based cluster node is developed. As a result of the modeling, the metrics Do, Daccs, and Scomm are obtained. The models are evaluated as to their complexity and precision by comparing the modeling results with the measured values of Do, Daccs, and Scomm. The primary contributions of this dissertation research are as follows. First, the metric Daccs and Scomm are introduced in order to complement the Do metric in its use for evaluation of the effects of optimizations in the networking subsystem on parallel performance in clusters. The metrics are shown to adequately describe CPSO performance effects. Second, a method for assessing performance effects of CPSO scenarios on application performance is developed and presented. Third, a set of analytical models of cluster node networking subsystems with CPSO capability is developed and characterised as to their complexity and precision of the prediction of the Do and Daccs metrics.

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Network administration has become more difficult as the number of Internet users has grown and customer usage patterns have changed over time. Rapidly increasing subscriber bases, data intensive applications (such as streaming audio and video), heavy Web browsing, and large file downloads require significant resources and may tax existing network bandwidth. Reliability and quality of service are becoming serious issues for service providers across the country. Due to the dynamic nature of the information technology (IT) sector in general, it is difficult to predict future network usage patterns or what types of applications may be available, and how these applications may be used over time. This research presents a methodology to facilitate capacity planning and to improve the evaluation of network performance for connection-based networks using the Virginia Tech modem pool as a test bed. The abstract research question is can innovative business strategies be employed in lieu of, or in addition to, traditional management practices such as adding capacity in order to improve the performance of a dialup network? Examples of such strategies or business rules may include limiting the duration of an online session or limiting the number of times a given customer can dial into the pool in a specified time period. A complete network traffic characterization is conducted based on service time and interarrival time variables. A longitudinal analysis is performed to examine how traffic patterns have changed over time. Finally, a simulation model is utilized to examine how imposing different business rules during peak-periods of operation can reduce the blocking probability and improve the overall level-of-service. The potential contribution of this research appears to be significant based on the lack of existing literature. / Ph. D.

Syfte och frågeställningar Syftet har varit är att öka kunskapen om lärares bedömning av elevers praktiska färdighet i innebandy på den nationella idrottsutbildningen (NIU). Vidare syftar studien till att jämföra lärarnas bedömning med kursplanens kunskapskrav. Vilka färdigheter är det som de intervjuade lärarna bedömer hos eleverna? Hur bedömer de intervjuade lärarna elevernas färdigheter? Hur erfar de intervjuade lärarna arbetet med bedömning och betygsättning? Metod Med hänsyn till studiens kvalitativa ansats valdes intervju som metod. Studien avgränsar sig till de lärare som undervisar innebandy som specialidrott. Urvalet gjordes med hänsyn till geografisk spridning. I studien deltog sex lärare från sex olika skolor i landet.Som teoretisk ansats användes en mätteori där verklighetsmängden, lärarnas uttryckta bedömningar, jämfördes mot symbolmängden, kursplanens uttryckta bedömningar. I analysen av lärarnas bedömning användes ”Performance analysis” som utgångspunkt. Resultat Resultatet visade att lärarna bedömde eleverna i teknik, tekniskt användande, taktik, rörelse, och beteende utifrån modellen ”Performance Analysis” samt fysisk förmåga och elevernas utveckling över tid. Bedömningarna skedde på olika sätt, men med en tyngdpunkt på den subjektiva bedömningen. Lärarna erfar betygsprocessen som utmanande och att riktlinjerna för bedömning är otydliga i styrdokumenten. Slutsats Lärarna är väl lämpade för att genomföra bedömningar på goda grunder utifrån forskning om idrottsliga prestationer. Deras erfarenhet tillsammans med de bedömningar de som de gör, ger en god grund för en prestationsbedömning. Det saknas dock tydliga riktlinjer från Skolverket och Svenska Innebandyförbundet om vilka färdigheter som ska bedömas och hur bedömningarna ska ligga till grund för betygsättningen. Detta innebär att bedömningen ser annorlunda ut från skola till skola och på det följer en betygssättning som riskerar att inte vara likvärdig. / Aim The aim of this study has been to investigate how teachers assess students practical skills in floorball at the Elite Sports Programs in the Swedish Upper Secondary School. Furthermore, the study aims to compare teachers assessment with the standards of attainment formulated by The Swedish National Agency for Education (SNAE) What skills do the interviewed teachers assess? How do the interviewed teachers assess the student’s skills? How do the interviewed teacher experience the work with assessment? Method With regards to the study's qualitative approach interview was chosen as method. The study delimits itself to the teachers who teach floorball as special sports. The selection was made taking into account the geographical spread and six teachers from six different schools participated in the study. As a theoretical approach, a measure theory were used where true amount, the teachers expressed assessments, compared to the symbol rate, the curriculum expressed judgments. The analysis of teachers' assessment used the model of "Performance analysis" as departure point. Results The results show that teachers assessed students in technique, technical use, tactics, movement and behavior based on the model, "Performance Analysis", as well as physical ability and pupils development over time. The assessment differed and there was an emphasis on a subjective assessment. Teachers experienced the grading process as challenging and fuzzy regarding the guidelines from the SNAE. Conclusion Teachers are well capable of assessing. Their basis for assessment is in accordance with research of athletic performance. There are no clear guidelines from SNAE or the Swedish Floorball Federation regarding the skills that should be assessed and furthermore how the assessment should form the basis for grading. This means that the assessment differs from school to school, with the risk that the grading is based on different grounds.

Yes / This study aims to explore how marketers can use text mining to analyze actors, actions and performance effects of service encounters by building on the role theory. This enables hotel managers to use introduced methodology to measure and monitor frontline employees’ role behavior and optimize their service. Design/methodology/approach: The authors’ approach links text mining and importance-performance analysis with role theory’s conceptual foundations taking into account the hotel industry’s specifics to assess the effect of frontline hotel employees’ actions on consumer satisfaction and to derive specific management implications for the hospitality sector. Findings: This study identifies different actors involved in hotel frontline interactions revealing distinct role behaviors that characterize consumers’ perspectives of service encounters with different role types associated with front-office employees. This research also identifies role performance related to role behavior to improve service encounters. Practical implications: Customer–employee interactions can be assessed by user-generated contents (UGC). Performance evaluations relate to frontline employee roles associated with distinct role scripts, whereby different hotel segments require tailored role designs. Insights of this study can be used for service optimization, market positioning as well as for improving human resource management practices in the hotel industry. Originality/value: This study contributes to the service encounter literature by applying role theory in the text mining of UGC to assess frontline employees as actors and the effects of their actions on service quality delivery. / Science Foundation of Ministry of Education, PR China (Grant No. 21YJA630031)

Providing performance and isolation guarantees for applications running in virtualized datacenter environments requires continuous management of the underlying physical resources. For communication- and I/O-intensive applications running on such platforms, the management methods must adequately deal with the shared use of the high-performance fabrics these applications require. In particular, new classes of latency-sensitive and data-intensive workloads running in virtualized environments rely on emerging fabrics like 40+Gbps Ethernet and InfiniBand/RoCE with support for RDMA, VMM-bypass and hardware-level virtualization (SR-IOV). However, the benefits provided by these technology advances are offset by several management constraints: (i) the inability of the hypervisor to monitor the VMs’ usage of these fabrics can affect the platform’s ability to provide isolation and performance guarantees, (ii) the hypervisor cannot provide fine-grained I/O provisioning or perform management decisions for VMs, thus reducing the degree of consolidation that can be supported on the platforms, and (iii) without such support it is harder to integrate these fabrics into emerging cloud computing platforms and datacenter fabric management solutions. This is made particularly challenging for workloads spanning multiple VMs, utilizing physical resources distributed across multiple server nodes and the interconnection fabric. This thesis addresses the problem of realizing a flexible, dynamic resource management system for virtualized platforms with high performance fabrics. We make the following key contributions: (i) A lightweight monitoring tool, IBMon, integrated with the hypervisor to monitor VMs’ use of RDMA-enabled virtualized interconnects, using memory introspection techniques. (ii) The design and construction of a resource management system that leverages IBMon to provide latency-sensitive applications performance guarantees. This system is built on microeconomic principles of supply and demand and can be deployed on a per-node (Resource Exchange) or a multi-node (Distributed Resource Exchange) basis. Fine-grained resource allocations can be enforced through several mechanisms, including CPU capping or fabric-level congestion control. (iii) Sphinx, a fabric management solution that leverages Resource Exchange to orchestrate network and provide latency proportionality for consolidated workloads, based on user/application-specified policies. (iv) Implementation and experimental evaluation using InfiniBand clusters virtualized with the Xen or KVM hypervisor, managed via the OpenFloodlight SDN controller, and using representative data-intensive and latency-sensitive benchmarks.

The spectrum has become one of the most important and scarce resources for future wireless communications. However, the current static spectrum policy cannot meet the increasing demands for spectrum access. To improve spectrum efficiency, dynamic spectrum access (DSA) attempts to allocate the spectrum to users in an intelligent manner. Cognitive radio (CR) is an enabling technology for DSA, and can maximize spectrum utilization by introducing unlicensed or secondary users (SUs) to the primary system. The key component of DSA is dynamic spectrum sharing (DSS), which is responsible for providing efficient and fair spectrum allocation or scheduling solutions among licensed or primary users (PUs) and SUs. This thesis focuses on the design of efficient DSS schemes for the future wireless communication networks. Firstly, based on the coordinated DSS model, this thesis proposes a heterogeneous-prioritized spectrum sharing policy for coordinated dynamic spectrum access networks. Secondly, based on the uncoordinated DSS model, a novel partial spectrum sharing strategy and the cross-layer optimization method have been proposed to achieve efficient spectrum sharing between two licensed networks. Then, a hybrid strategy which combines the overlay and underlay schemes is proposed under uncoordinated DSS model. The proposed analytical methods can provide efficient and accurate modeling to predict the behaviors of the PUs and SUs in DSS systems. This thesis presents the performance prediction of the proposed novel DSS schemes that achieve efficient spectrum sharing for coordinated and uncoordinated future wireless networks.