Until the developments in computer technology, linear test administrations within classical test theory framework is mostly used in testing practices. These tests contain a set of predefined items in a large range of difficulty values for collecting information from students at various ability levels. However, placing very easy and very difficult items in the same test not only cause wasting time and effort but also introduces possible extraneous variables into the measurement process such as possibility of guessing, chance of careless errors induced by boredom or frustration. Instead of administering a linear test there is another option that adapts the difficulty of test according to the ability level of examinees which is named as computerized adaptive test. Computerized adaptive tests use item response theory as a measurement framework and have algorithms responsible for item selection, ability estimation, starting rule and test termination. The present study aims to determine the applicability of computerized adaptive testing (CAT) to Turkish Pupil Monitoring System&rsquo / s (PMS) mathematics assessments. Therefore, live CAT study using only multiple choice items is designed to investigate whether to obtain comparable ability estimations. Afterwards, a Monte Carlo simulation study and a Post-hoc simulation study are designed to determine the optimum CAT algorithm for Turkish PMS mathematics assessments. In the simulation studies, both multiple-choice and open-ended items are used and different scenarios are tested regarding various starting rules, termination criterion, ability estimation methods and existence of exposure/content controls. The results of the study indicate that using Weighted Maximum Likelihood (WML) ability estimation method, easy initial item difficulty as starting rule and a fixed test reliability termination criterion (0.30 standard error as termination rule) gives the optimum CAT algorithm for Turkish PMS mathematics assessment. Additionally, item exposure and content control strategies have a positive impact on providing comparable ability estimations.

This study has been assigned by Bengt Hellman who works at the logistic department at IKEA Torsvik just outside of Jönköping. The task has been to develop a new picking strategy for the Oversize area in the CDC-Warehouse. The reason why IKEA wants a new strategy is because they want to minimize the route length for the forklifts when collecting the orders. By evaluating the current strategies on other areas in the CDC-storehouse, study literature within this subject and look at restrictions for the storing of goods, we have analyzed how the Oversize area works today. We compared the gathered information, to how it should be done according to the literature to be able to work out a new functional strategy. Today, IKEA does not have a working strategy for the oversize area because of lack of time and because all the power has been put on other areas were sales rates are currently higher. This have led to lack of organisation at the Oversize area and items are just put were there is space without first analysing were it should be placed. The strategy that we have worked out and introduced to IKEA builds on easiness of understanding the layout, the employees shall know why an item is placed where it is. We have also analyzed which items that are frequently ordered with each other. We have put weight on trying to keep those items as close as we can to minimize the route length for the forklifts. To help IKEA with reorganizations in the future we have made it as easy as we could to move high- and low frequently items around and also introducing new articles in the storehouse, this by the reason that sales rate can change drastically when a new sales campaign is initiated by IKEA / Detta examensarbete är utfört på önskemål av Bengt Hellman som arbetar på logistikavdelningen på IKEA Torsvik utanför Jönköping. Arbetet har gått ut på att ta fram ett nytt förslag på hur de skall placera sina artiklar på plocknivå (vad IKEA kallar för mappning) inne på Oversize avdelningen på IKEA:s CDC-lager. Anledningen till detta är att IKEA vill minska sina körsträckor för plockarna inne på lagret och därmed öka effektiviteten. Genom att studera befintliga mappningsstrategier som redan finns på övriga avdelningar på CDC-lagret, litteraturstudier och titta på vilka begränsningar som finns inne på lagret så har vi analyserat nuläget mot teori för att sedan kunna ta fram en ny strategi för hur en fungerande mappning skulle kunna se ut. I dag så finns det inte någon väl utarbetat strategi för mappningen på Oversize avdelningen, detta på grund av att andra avdelningar prioriterats på grund av att de säljer mycket mer i dagsläget. Detta har även medfört att den huvudsakliga uppdelning som fanns tidigare på Oversize avdelningen med affärsområden har fått stå åt sidan på grund av tidsbrist och artiklar har placerats in där det finns plats istället för att analysera var de kan placeras bäst. Det nya förslaget som vi presenterar för IKEA bygger på att det skall vara enkelt att förstå layouten, plockarna skall veta varför en artikel finns där den finns. Vi har även tagit stor hänsyn till vad som säljs med vad och försökt placera dessa artiklar i närheten av varandra för att på så sätt minska körsträckorna. Vi har även haft i åtanke att det skall vara enkelt att placera om hög och lågfrekventa artiklar samt nyheter inne på lagret då försäljningsvolym påverkas väldigt mycket utav olika kampanjer som IKEA har.

The objectives of this study were to validate the Maslach Burnout Inventory - General Survey (MBI-GS) and the Oldenburg Burnout Inventory (OLBI), to determine the construct equivalence and item bias of these instruments for employees in an earthmoving equipment industry in South &ca of different language groups, to determine the correlation between the MBI-GS and the OLBI, and to investigate the relationship between burnout and various demographic characteristics. A random sample of 326 employees in an earthmoving equipment industry of eight provinces in South Africa was taken. The MBI-GS, the OLBI and a biographical questionnaire were used as measuring instruments. Cronbach alpha coefficients, inter-item correlation coefficients, Pearson product-moment correlation coefficients and exploratory factor analysis were used to analyse the data The results showed that three factors of the MBI-GS and two factors of the OLBI exist for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the three factors of the MBI-GS and the two factors for the OLBI for different language groups. No evidence was found for uniform or non-uniform bias of the items of the MBI-GS or the OLBI for different language groups. Results indicated that no differences with respect to levels of burnout exist between various demographic characteristics. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

Background. Police work is a stressful occupation with frequent exposure to traumatic events and psychological strain from work might increase the risk of burnout. This thesis focuses on patrolling police officers (PPO), who work most of their time in the community and have daily contact with the public. Since police work traditionally is a male coded occupation we assume that there are differences between women and men in burnout as well as experiences from psychosocial work environment. Aim. The overall aim of this thesis is to explore burnout, psychosocial and physical work environment, coping strategies, and stress of conscience when taking gender into consideration among patrolling police officers. Methods. This thesis employs both qualitative and quantitative methods. In Paper I a qualitative approach with narrative interviews was used where male PPO described experiences of traumatic situations when caring for victims of traffic accidents. A convenience sample of nine male PPO from a mid-sized police authority was recruited. Interviews were analyzed using qualitative content analysis. Papers II, III, and IV were based on a cross-sectional survey from a randomly selected sample stratified for gender from all 21 local police authorities in Sweden. In the final sample, 1554 PPOs were invited (778 women, 776 men), response rate was 55% (n=856) in total, 56% for women (n=437) and 53% for men (n=419). The survey included a self-administered questionnaire based on instruments measuring burnout, stress of conscience, psychosocial and physical work environment, and coping. Results. Findings from Paper I were presented in three themes; “being secure with the support system,” “being confident about prior successful actions,” and “being burdened with uncertainty.” Results from Paper II showed high levels of emotional exhaustion (EE), 30% for female PPOs and 26% for male PPOs. High levels of depersonalization (DP) were reported for 52 % of female PPO, corresponding proportions for male were 60%. Multiple logistic regression showed that stress of conscience (SCQ-A), high demand, and organizational climate increased the risk of EE for female PPO. For male PPO stress of conscience (SCQ-A), low control and high demand increased the risk of EE. Independent of gender, stress of conscience (SCQ-A) increased the risk of DP. Psychometric properties of the WOCQ were investigated with exploratory factor analysis and confirmatory factor analysis, a six-factor solution was confirmed. DIF analysis was detected for a third of the items in relation to gender. In Paper IV a block wise hierarchical multiple regression analysis was performed investigating the predictive impact of psychological demand, decision latitude, social support, coping strategies, and stress of conscience on EE as well as DP. Findings revealed that, regardless of gender, risk of EE and DP increased with a troubled conscience amongst the PPO. Conclusion. “Being burdened with uncertainty” in this male-dominated context indicate that the PPO did not feel confident talking about traumatic situations, which might influence their coping strategies when arriving to a similar situation. This finding can be related to Paper II and IV showing that stress of conscience increased the risk of both EE and DP. The associations between troubled conscience and the risk of experiencing both emotional exhaustion and depersonalization indicate that stress of conscience should be considered when studying the influence of the psychosocial work environment on burnout. Results from this study show that the psychosocial work environment is not satisfying and needs improvement for patrolling police officers in Sweden. Further studies including both qualitative and quantitative (longitudinal) methods should be used to improve knowledge in this area to increase conditions for preventive and rehabilitative actions.

This study formed part of a larger project that is concerned with the adaptation of a test of cognitive academic language proficiency, the Woodcock Muñoz Language Survey (WMLS). The WMLS has been adapted from English into isiXhosa and the present study is located within the broader study that is concerned with establishing overall equivalence between the two language versions of the WMLS. It was primarily concerned with the Verbal Analogies (VA) scale. Previous research on this scale has demonstrated promising results, but continues to find evidence of some inequivalence. This study aimed to cross-validate previous research on the two language versions of the WMLS and improve on methodological issues by employing matched groups. It drew upon an existing dataset from the larger research project. The study employed a monolingual matched two-group design consisting of 150 mainly English speaking and 149 mainly isiXhosa learners in grades 6 and 7. This study had two sub aims. The first was to investigate item bias by identifying DIF items in the VA scale across the isiXhosa and English by conducting a logistic regression and Mantel-Haenszel procedure. Five items were identified by both techniques as DIF. The second sub aim was to evaluate construct equivalence between the isiXhosa and English versions of the WMLS on the VA scale by conducting a factor analysis on the tests after removal of DIF items. Two factors were requested during the factor analysis. The first factor displayed significant loadings across both language versions and was identified as a stable factor. This was confirmed by the Tucker’s Phi and scatter plot. The second factor was stable for the English version but not for the isiXhosa version. The Tucker’s phi and scatter plot indicated that this factor is not structurally equivalent across the two language versions / Magister Artium (Psychology) - MA(Psych)

Explicating the nature and concomitants of eudaimonic well-being is currently at the forefront of research on a fulfilling life and functioning well. However, the strength of research conducted on constructs is dependent on the quality of instrumentation. In view of this notion, Waterman et al. (2010) developed the Questionnaire for Eudaimonic Well-Being (QEWB) to operationalise their conceptualisation of eudaimonic well-being and explored the scale’s validity in American student samples. In particular, they confirmed a good fit of a unidimensional factor structure by using parcelled indicators in confirmatory factor analysis. Research on the applicability of this measure within the other cultural contexts needs to take cognisance of aspects such as conceptual equivalence, translation issues, and validity criteria. To contribute to the adaptation of the QEWB for the multilingual South African context, the aim of this study was to explore the structural and external validity of English, Afrikaans, and Setswana versions of the QEWB. A cross-sectional questionnaire survey design was used for data gathering. The sample (n = 975) consisted of students from a large university in South Africa, who completed either the English (n = 325), Afrikaans (n = 478), or Setswana (n = 172) version of the scale. To investigate the structural validity of the scale, descriptive statistics, reliability coefficients, and the scale’s factor structure were scrutinised. Regarding the latter, confirmatory factor analyses with both parcel- and item-level indicators, as well as principal component analyses were examined to assess the fit of a one-factor model. Exploratory factor analyses were conducted to further explore the dimensionality of the scale. External validity was examined by considering the attenuation corrected correlational patterns between scores on the QEWB and measures of well-being and ill-being. Results showed that item- and scale-level scores were mostly negatively skewed, with high average scores. Internal consistency reliability statistics indicated satisfactory reliability, except for a small mean interitem correlation for the Setswana instrument. Although adequate goodness of fit statistics of parcel-level confirmatory factor analyses supported Waterman et al.’s (2010) notion of a one-factor structure, the assumption of unidimensionality within parcels was not satisfied, which suggested that these analyses could have masked multidimensionality. A lack of fit of the one-factor model was shown by a number of small or negative interitem and item-total correlations, insufficient fit indices for item-level confirmatory factor analyses, and a small proportion of variance explained by the first unrotated component in principal component analysis. Exploratory factor analyses indicated a three-factor model, where the factors Sense of Purpose, Active Involvement in Beliefs, and Effortful Engagement were distinguished. For the English scale, a four-factor model was also sensible. Items that may need modification for the current context were identified. Support for convergent and discriminant validity was established. This study contributed to a further validation of the QEWB and highlighted its multidimensional structure for the groups involved. Further evaluation of the scale on conceptual and empirical levels is indicated, also specifically for applicability within the South African multilingual context. / Thesis (MSc (Clinical Psychology)--North-West University, Potchefstroom Campus, 2013.

Explicating the nature and concomitants of eudaimonic well-being is currently at the forefront of research on a fulfilling life and functioning well. However, the strength of research conducted on constructs is dependent on the quality of instrumentation. In view of this notion, Waterman et al. (2010) developed the Questionnaire for Eudaimonic Well-Being (QEWB) to operationalise their conceptualisation of eudaimonic well-being and explored the scale’s validity in American student samples. In particular, they confirmed a good fit of a unidimensional factor structure by using parcelled indicators in confirmatory factor analysis. Research on the applicability of this measure within the other cultural contexts needs to take cognisance of aspects such as conceptual equivalence, translation issues, and validity criteria. To contribute to the adaptation of the QEWB for the multilingual South African context, the aim of this study was to explore the structural and external validity of English, Afrikaans, and Setswana versions of the QEWB. A cross-sectional questionnaire survey design was used for data gathering. The sample (n = 975) consisted of students from a large university in South Africa, who completed either the English (n = 325), Afrikaans (n = 478), or Setswana (n = 172) version of the scale. To investigate the structural validity of the scale, descriptive statistics, reliability coefficients, and the scale’s factor structure were scrutinised. Regarding the latter, confirmatory factor analyses with both parcel- and item-level indicators, as well as principal component analyses were examined to assess the fit of a one-factor model. Exploratory factor analyses were conducted to further explore the dimensionality of the scale. External validity was examined by considering the attenuation corrected correlational patterns between scores on the QEWB and measures of well-being and ill-being. Results showed that item- and scale-level scores were mostly negatively skewed, with high average scores. Internal consistency reliability statistics indicated satisfactory reliability, except for a small mean interitem correlation for the Setswana instrument. Although adequate goodness of fit statistics of parcel-level confirmatory factor analyses supported Waterman et al.’s (2010) notion of a one-factor structure, the assumption of unidimensionality within parcels was not satisfied, which suggested that these analyses could have masked multidimensionality. A lack of fit of the one-factor model was shown by a number of small or negative interitem and item-total correlations, insufficient fit indices for item-level confirmatory factor analyses, and a small proportion of variance explained by the first unrotated component in principal component analysis. Exploratory factor analyses indicated a three-factor model, where the factors Sense of Purpose, Active Involvement in Beliefs, and Effortful Engagement were distinguished. For the English scale, a four-factor model was also sensible. Items that may need modification for the current context were identified. Support for convergent and discriminant validity was established. This study contributed to a further validation of the QEWB and highlighted its multidimensional structure for the groups involved. Further evaluation of the scale on conceptual and empirical levels is indicated, also specifically for applicability within the South African multilingual context. / Thesis (MSc (Clinical Psychology)--North-West University, Potchefstroom Campus, 2013.

The objectives of this study were to validate the Maslach Burnout Inventory - General Survey (MBI-GS) and the Oldenburg Burnout Inventory (OLBI), to determine the construct equivalence and item bias of these instruments for employees in an earthmoving equipment industry in South &ca of different language groups, to determine the correlation between the MBI-GS and the OLBI, and to investigate the relationship between burnout and various demographic characteristics. A random sample of 326 employees in an earthmoving equipment industry of eight provinces in South Africa was taken. The MBI-GS, the OLBI and a biographical questionnaire were used as measuring instruments. Cronbach alpha coefficients, inter-item correlation coefficients, Pearson product-moment correlation coefficients and exploratory factor analysis were used to analyse the data The results showed that three factors of the MBI-GS and two factors of the OLBI exist for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the three factors of the MBI-GS and the two factors for the OLBI for different language groups. No evidence was found for uniform or non-uniform bias of the items of the MBI-GS or the OLBI for different language groups. Results indicated that no differences with respect to levels of burnout exist between various demographic characteristics. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

By the emergence of electronic commerce and low transaction costs on the Internet, an interest in the design of new auction mechanisms has been arisen. Recently many researchers in computer science, economics, business, and game theory have presented many valuable studies on the subject of online auctions, and auctions theory. When faced from a computational perspective, combinatorial auctions are perhaps the most challenging ones. Combinatorial auctions, that is, auctions where bidders can bid on combinations of items, tend to lead to more efficient allocations than traditional auction mechanisms in multi-item multi-unit situations where the agents&rsquo / valuations of the items are not additive. However, determining the winners to maximize the revenue is NP-complete. In this study, we first analyze the existing approaches for combinatorial auction problem. Based on this analysis, we then choose three different approaches, which are search approach, descending simultaneous auctions approach, and IP (Integer Programming) formulation approach to build our models. The performances of the models are compared using computer simulations, where we model bandwidth allocation system. Finally a combinatorial auction tool is built which can be used for online auctions and e-procurement systems.

Differential Item Functioning Analyses investigates whether individuals with same ability in different groups also show similar performance on an item. In matching the individuals of the same ability, most of the methodologies use total scores of the tests which are usually constructed to be unidimensional. th purpose of the present study is evaluating the PISA 2003 mathematics literacy items through the use of DIF methodology which uses a multidimensional approach in matching students instead of single total score, improve the matching for DIF analyses. In the study factor structure of the tests will be determeined via both exploratory and confirmatory analyses in a complimentary fashion. then DIF analyses conducted using Logistic regression (LR) and Mantel -Haenszel methods.Analyses showed that the matching criterion improved when multivariate analyses were used. the number of DIF items was decreased when the matching criterion is defined based on multiple criterion scores such as mathematical literacy and problem solving scores or two different mathematical literacy subtest score. In addition, qualitative reviews and examination of the distribution of DIF items by content categories, cognitive demands, item types,item text, visual-spatial factors and linguistic properties of items were analyzed to explain the differential performance. Curriculum, cultural and translation differences were the main criteria for the qualitative analyses of DIF items. The results imply that curriculum and translation differences in items might be causing the DIF across Turkish and English versions of the tests.