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Service systems such as call centers and hospital inpatient wards typically feature multiple classes of customers and multiple types of servers. Not all customer-server pairs are compatible, and some types of servers may be more efficient at serving some classes of customers than others. In the queueing literature, the problem of matching customers and servers is known as skills-based routing. This thesis consists of two works I have done in this area. The first work, which is done jointly with Jing Dong and Pengyi Shi, considers the routing problem in the face of a demand surge such as a pandemic. It shows how future arrival rate information, which is often available through demand forecast models, can be used to route near-optimally, even when there may be prediction errors. The methods used involve fluid approximations and optimal control theory, and the policies obtained are intuitive and easy to implement. The second work, which is done jointly with Jing Dong, incorporates a staffing element in addition to routing. Asymptotically optimal staffing and scheduling policies are derived for an M-model, both with and without demand uncertainty. The methods used involve diffusion approximations and stochastic-fluid approximations.

Computer-assisted language learning (CALL) programs developed earlier for vocabulary acquisition employed mainly word-list pedagogy and could not present information in a real world context. Advancement in computer technology has triggered the development of multimedia CALL programs which can present information in different formats using graphics, sound, text, and video with links to other chunks of information. The purpose of this study was to examine the effects of two multimedia CALL programs on vocabulary acquisition. Participants were 86 intermediate level English as a second language (ESL) students. They were randomly assigned to one of two treatment groups. Students in group one viewed a program with Motion Graphics and text. Students in group two viewed a program that had Still Graphics and text. Their task was to study ten names of hand and power tools. Both groups took the pretest, viewed the video of the tools, had an immediate posttest and a two-week delayed posttest.The results yielded no treatment effects. Further analysis revealed time effects but no interaction between treatment and time. Students who learned through Motion Graphics performed significantly better on the recall tests than those who learned through Still Graphics. Further research in this area involving the use of various graphic formats in a CALL environment is needed. / Ph. D.

<p dir="ltr">Container orchestration systems, such as Kubernetes, often rely on manual resource allocation to manage resources, which can be inefficient and inflexible due to frequent over-provisioning or underprovisioning. Kubernetes horizontal pod autoscaler (HPA), vertical pod autoscaler (VPA), and Google Kubernetes Engine (GKE) Autopilot are primarily threshold-based, making them reactive rather than proactive since they adjust resources after exceeding utilization thresholds, leading to temporary degradation in quality of service~(QoS). While some solutions utilize calls per minute (CPM) counts for requests to microservices to estimate resource consumption dynamically, they do not fully exploit distributed traces or associated microservices' interdependencies. This thesis hypothesizes that more profound insights into future workload patterns can be gained by exploiting microservices' interaction and the CPM counts for each pair of communicating microservices. This thesis proposes a comprehensive machine learning workflow to assess whether factoring in the interdependencies between microservices results in improved workload prediction. The findings of this study indicate that a long short-term memory (LSTM) model performs well, with average mean absolute error (MAE) and root mean square error (RMSE) values of 7.02 and 10.54, respectively. The highest \(R^2\) score observed was 0.07. This suggests that although incorporating distributed traces and inter-microservice CPM counts provides valuable insights, the models fail to capture the full complexity of workload dynamics. These results highlight the potential for enhancing workload prediction accuracy and underscore the need to refine these methods further to achieve more proactive and efficient resource allocation in container orchestration systems.</p>

Acoustic communication in anurans plays a critical role in species recognition, defending territories and resources, and finding a mate. Anurans use a number of different call note types to communicate, from which the most notable are advertisement- and aggression calls. Optimum weather conditions are a precursor to the commencement of the breeding season for all frog species and their calling behaviour is therefore readily influenced by atmospheric conditions. Male frogs within a chorus also tend to call from territories within a specific range of distances from one another. The objectives of this study were to 1) determine a possible context in which call note types are produced, 2) to determine the effect of atmospheric conditions on calling behaviour and 3) to determine the spacing distances between males and females in a chorus of Queckett’s River Frog (Amietia quecketti). Pre-recorded note types were used in a playback experiment to determine a context for elicited responses. A context was derived for six of the responses. Advertisement (clicks and whines), aggression (creaks), encounter (tonal notes), territorial (whine-tonal notes), and release calls (squeaks) were described. Calls and atmospheric conditions were recorded and correlated for an entire breeding season. Water temperature, wind speed, humidity and barometric pressure had a significant effect on calling intensity. As water temperature decreased calling intensity increased, while increased wind temperature led to increased calling intensity. Amietia quecketti calls from the water, explaining the effect while increased wind speed decreases water temperature and can carry sound further. Both humidity and barometric pressure showed increased calling intensity only at specific levels. Humidity and barometric pressure have a direct effect on one another, which most likely causes the correlation between calling intensity and both these variables. In this study A. quecketti was shown to have breeding ponds for males and resting ponds and positions for non-gravid females. This prevents unwanted or unnecessary amplexus. Males showed much smaller and less variable territory sizes than females. This is most likely because males have a small range of optimal spacing distance while females move towards and away from males. The presence of vegetation resulted in smaller territories. This is possibly because smaller males act as satellite males and cannot be seen by larger males in vegetation. The size of males did not affect territory size. Males have a specific inter-male spacing distance regardless of size. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Acoustic communication in anurans plays a critical role in species recognition, defending territories and resources, and finding a mate. Anurans use a number of different call note types to communicate, from which the most notable are advertisement- and aggression calls. Optimum weather conditions are a precursor to the commencement of the breeding season for all frog species and their calling behaviour is therefore readily influenced by atmospheric conditions. Male frogs within a chorus also tend to call from territories within a specific range of distances from one another. The objectives of this study were to 1) determine a possible context in which call note types are produced, 2) to determine the effect of atmospheric conditions on calling behaviour and 3) to determine the spacing distances between males and females in a chorus of Queckett’s River Frog (Amietia quecketti). Pre-recorded note types were used in a playback experiment to determine a context for elicited responses. A context was derived for six of the responses. Advertisement (clicks and whines), aggression (creaks), encounter (tonal notes), territorial (whine-tonal notes), and release calls (squeaks) were described. Calls and atmospheric conditions were recorded and correlated for an entire breeding season. Water temperature, wind speed, humidity and barometric pressure had a significant effect on calling intensity. As water temperature decreased calling intensity increased, while increased wind temperature led to increased calling intensity. Amietia quecketti calls from the water, explaining the effect while increased wind speed decreases water temperature and can carry sound further. Both humidity and barometric pressure showed increased calling intensity only at specific levels. Humidity and barometric pressure have a direct effect on one another, which most likely causes the correlation between calling intensity and both these variables. In this study A. quecketti was shown to have breeding ponds for males and resting ponds and positions for non-gravid females. This prevents unwanted or unnecessary amplexus. Males showed much smaller and less variable territory sizes than females. This is most likely because males have a small range of optimal spacing distance while females move towards and away from males. The presence of vegetation resulted in smaller territories. This is possibly because smaller males act as satellite males and cannot be seen by larger males in vegetation. The size of males did not affect territory size. Males have a specific inter-male spacing distance regardless of size. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

The purpose of this study was to determine whether there is a relationship between perceived emotional intelligence and job performance among inbound call centre leaders in the medical aid environment. The sample consisted of 268 participants (45 leaders and 223 raters) across different age and race groups. A convenience sample was used, since it was easier to focus on call centre leaders working in the same office. All of the participants completed the 360º Emotional Competency Profiler (ECP) in order to measure emotional intelligence whereas the job performance data were obtained from the management team and an average score of their performance over a one-year period was examined. The research results show that there was no statistically significant relationship between emotional intelligence and job performance among the call centre leaders. / Industrial and Organisational Psychology / M.A. (Industrial and Organisational Psychology )

The effectiveness of e-mail writing has been exhaustively studied and reported on, especially in Taiwan. However, there has not been any research carried out on the topics that mainland Chinese university students enjoy writing about when corresponding with their Western epals, nor does the literature report research on writing e-mails to two groups of epals simultaneously. This study explores what issues concerned the participants when they exchanged e-mails with their Western epals and how they viewed their cross-cultural learning experience. The participants were 28 mainland Chinese second-year English majors who voluntarily corresponded with 28 American high school pupils and 28 Western adult epals for about two months in Autumn 2006. The data of this exploratory interpretative research was mainly collected from their e-mails, ‘final reports’, the mid-project questionnaire, and semi-structured interviews. The study found that the topics the participants enjoyed writing about actually depended on with whom they were corresponding. With the younger school pupils, they tended to look for friendship by talking about pastimes, their own high school experience, etc. To the more sophisticated adult epals though, they wrote largely about personal matters, on which they seemed to be covertly seeking advice. However, some topics were common to both groups and were equally popular – for example, school and daily life. The data also reveals that the majority of the participants enjoyed the experience and overall had positive views about it. These fall into three broad categories of learning: language, cultural, and communication. However, some experienced minor difficulties and problems in these areas, particularly regarding the communication aspect. Meanwhile, in the process of the participants multiediting their ‘final reports’, learning seems to have occurred between their first and final drafts – perhaps as a result of responding to the researcher’s written feedback, which seemed to make a significant difference. The implications arising from the study suggest that the students’ interest in it stimulated their engagement with learning - though the findings are tentative. Some recommendations for further research are also given.

Submitted thesis focuses on call center staff turnover. After short reference to work psychology and organization the theoretic part deals mainly with the characterization of this phenomenon. It aims to specify the main factors and it refers to possible stabilization measures. The second theme of the thesis is call centre and work of operators. Possible difficulties and risks of this job are described, the profesiogram of an employee of the particular selling point has been compiled. The last chapter deals with recruitment procedure. It specifies the single phases of the selection procedure, beginning with the preparation and compilation of necessary documents and ending with adaptation phase of a new employee at the end of the whole procedure. The empirical part of the thesis focuses on the turnover in company "A". The analysis of the personnel data from 2009 to October 2010 was the first step. Subsequently we tried to answer the question, if it is possible to use Time Crirtical Desecion Making Test (used in current selective procedure), sociability, ability to assert oneself a comunicability as predictors of continuance in company. As a diagnostic method the Bochum Personality Questionnaire was used.

Made available in DSpace on 2016-04-04T18:27:33Z (GMT). No. of bitstreams: 1 dissertacaocompleta.pdf: 481434 bytes, checksum: 23fdd2c3f992e2542f45e4efcb4bcc52 (MD5) Previous issue date: 2004-02-26 / The purpose of this paper is to verify the relationship among stress, quality of life, pleasure and suffering on the job of attending employees in a Call Center Unit in the city of Uberl?ndia-M.G. (Brazil). Some 162 employees volunteered to participate in the research of which 65,4% were female, 34% were male. 80% of the total were single and the average age was approximately 23 years old. In relation to the education the majority had high school diploma. The questionnaires, given in groups or individually, included an identification form and a sample of socio-demografic data, an Inventory of Stress Symptoms, Inventory of Ufe Quality and a Scale of Pleasure and Suffering at Work. Through the statistic analysis, it was observed meaningful associations among stress, life quality, pleasure and suffering at work. The presence of stress had a negative correlation with the social, professional and health of life quality quadrants. There was not a meaningful correlation between stress and affective quadrant. Pleasure at work was related positively with ali the quadrants of life quality. The suffering at work contributed to the failure in the social, professional and health quadrants. It was concluded that stress, pleasure and suffering at work are directly related to several dimensions of life quality. / O objetivo deste estudo foi verificar a rela??o entre stress, qualidade de vida, prazer e sofrimento no trabalho dos atendentes de um Call Center na cidade de Uberl?ndia/M.G. Participaram desse estudo 162 funcion?rios volunt?rios, sendo 65,4% do sexo feminino, 34% do sexo masculino e 0,6% n?o informou. Oitenta por cento eram solteiros e a m?dia de idade foi de 23 anos. Quanto ? escolaridade, houve predom?nio do Ensino M?dio. Os instrumentos, aplicados em grupo ou individualmente, inclu?ram ficha de identifica??o e coleta dos dados s?cio-demogr?ficos, Invent?rio de Sintomas de Stress, Invent?rio de Qualidade de Vida e Escala de Prazer e Sofrimento no Trabalho. Atrav?s de an?lises estat?sticas, foram observadas rela??es significativas entre o stress, a qualidade de vida, o prazer e o sofrimento no trabalho. A presen?a de stress demonstrou correla??o negativa com os quadrantes social, profissional e de sa?de da qualidade de vida. N?o houve correla??o significativa entre stress e quadrante afetivo. O prazer no trabalho relacionou-se positivamente com todos os quadrantes da qualidade de vida. O sofrimento no trabalho contribuiu para o fracasso nos quadrantes social, profissional e de sa?de. Conclui-se que o stress, prazer e sofrimento no trabalho est?o diretamente relacionados ?s v?rias dimens?es da qualidade de vida.