Peer-to-peer (P2P) paradigm, for its scalability and low cost management, is widely used in today’s network. Based on the typical designs for request/response services, a lot of efforts have been made to support publish-subscribe services in P2P networks. Gossip-based publish-subscribe system, which is commonly used in unstructured P2P networks, can provide great flexibility in query language and does not require special efforts on maintaining topology. The purpose of our work is to investigate effective and efficient mechanisms to build gossip-based publish-subscribe systems in unstructured P2P networks. Specifically, the probabilistic bi-quorum system (PBQS), for its assurance in effectiveness, becomes the object of our study. Uniform sampling is a fundamental tool to construct PBQS. By adopting uniform sampling, PBQS provides a bound on the likelihood that data messages will find a copy of the subscription. A random walk of length O(log n) is commonly used to gain a uniform sample on an expander graph of size n. To obtain a multitude of uniform samples thus requires an equivalent number of random walks of length O(log n) each. A number of works have relied on the Chernoff bound to analytically reduce the overhead needed to obtain a multitude of uniform samples. Besides, researchers have also shown that it is not necessary to replicate both data and query on uniformly chosen nodes. Alternatively, BubbleStorm performs controlled flooding on a constructed overlay to build PBQS. BubbleStorm does not require nodes forming a bubble to be uniformly chosen at random, and the probabilistic bound computed by BubbleStorm is different from uniform sampling based PBQS. In this thesis, we first show that the Chernoff bound on the statistical properties of samples collected from a random walk does not help in selecting uniformly random nodes. We then re-examine the role of uniform sampling in PBQS, and found that when multiple data answer a single subscription, it is sufficient and necessary for each data to be distributed uniformly at random. Looking into BubbleStorm, we examine more closely the probabilistic bound provided by this system. We found that, unlike uniform sampling based PBQS, the bubble intersection in BubbleStorm is distance dependent. Given a specific pair of publisher-subscriber, the data may never find the subscription. We further investigate the topology construction and found that re-creating topology prior to each controlled flooding or keeping topology with high degree of churn can help alleviate the distance dependency problem. We arrive at the conclusion that BubbleStorm construction is equivalent to caching of random walks. We show that re-using this cache to obtain samples over time leads to degradation of uniformity of the samples. We evaluate topology re-wiring as a simple method to keep the cache fresh, thereby benefiting from the low latency of controlled flooding without degrading the uniformity of samples over time. / published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

When designing work tasks, one goal should be to enable postures that maximize the force capabilities of the workers while minimizing the overall muscular demands; however, little is known regarding specific shoulder tissue loads during pushing and pulling. This study quantitatively evaluated the effects of direction (anterior-posterior pushing and pulling), handle height (100 cm and 150 cm), handle orientation (vertical and horizontal), included elbow angle (extended and flexed) as well as personal factors (gender, mass and stature) on hand force magnitudes, shoulder and L5/S1 joint moments, normalized mean muscle activation and electromyography (EMG)/force ratios during two-handed maximal push and pull exertions. Twelve female and twelve male volunteers performed maximal voluntary isometric contractions under 10 push and pull experimental conditions that emulated industrial tasks. Hand force magnitudes, kinematic data and bilateral EMG of seven superficial shoulder and trunk muscles were collected. Results showed that direction had the greatest influence on dependent measures. Push exertions produced the greatest forces while also reducing L5/S1 extensor moments, shoulder moments with the 150 cm height and overall muscular demands (p < 0.0001). The 100 cm handle height generated the greatest forces (p < 0.0001) and reduced muscular demands (p < 0.05), but were associated with greater sagittal plane moments (p < 0.05). Females generated, on average, 67% of male forces in addition to incurring greater muscular demands (p < 0.05). The flexed elbows condition in conjunction with pushing produced greater forces with reduced overall muscular demands (p < 0.0001). Furthermore, horizontal handle orientation caused greater resultant moments at all joints (p <. 0.05) The results have important ergonomics implications for evaluating, designing or modifying workstations, tasks or equipment towards improved task performance and the prevention of musculoskeletal injuries and associated health care costs.

Proactive ergonomics is generally considered to be a more efficient and cost effective way of designing working environments than reactive ergonomics. It often requires preemptively selecting working postures and forces to reduce potential injury risk. One major issue with proactive ergonomic design is correctly identifying the true manual forces that will be required of a worker to complete defined tasks. Typically, these forces are represented as in direct opposition to the forces required by a particular task. However, this is likely an oversimplification as forces often act in different directions than the task-required direction to increase required force level, enhance balance and reduce joint moments, depending on specific experimental conditions. This study aims to quantify these off-axis forces as they change with different required on-axis force intensities. This thesis evaluated the effects of force intensity on the presence of off-axis forces across four conditions, which included free and constrained postures, and with and without off-axis force. Eighteen female subjects performed static, unilateral, manual pushing and pulling exertions while seated and were limited to force contributions from the right upper extremity. Hand forces and location of bony landmarks were collected from each subject and force intensity consisted of both maximal and submaximal levels (5% to 50% of the maximum producible on-axis force in increments of 5%). All principle direction forces were scaled to the on-axis force level and anatomically relevant joint moments scaled to the maximum capacity joint moment. The main objective of this study was to analyze off-axis force production as force intensity was increased under various constraint conditions. The highest maximum on-axis force was in the fully free condition (off-axis force allowed and posture unconstrained) and as conditions became more constrained for both pushing and pulling exertions, maximum on-axis force production decreased (p=<0.0001). For submaximal exertions in the free posture, participants used off-axis forces to target the shoulder flexion-extension moment by pushing increasingly upwards (p=0.0122) and to the left by 5.6% on-axis (p=0.0025), and by pulling 12.6% on-axis downward (p=<0.0001) and 4.7% on-axis rightward (p=0.0024) compared to when off-axis force was not allowed. When comparing the free to the constrained posture while allowing off-axis force, participants pushed downwards instead of upwards by a difference of 12.9% on-axis (p=0.0002) and pulled less downward (becoming slightly upward) by an increasing difference (p=0.0002) and from decreasing to increasing rightward (p=0.0006). These changes in off-axis force showed a unifying strategy of using less shoulder flexion-extension strength by targeting wrist and elbow moments for pushing and pulling exertions. When in the constrained posture allowing and not allowing off-axis force resulted in more internal elbow flexion (p=0.0003) moment during pushing, and less internal shoulder flexion (p=0.0092), more internal shoulder adduction (p=0.0252), more to less internal elbow supination (p=0.0415), and increasingly less internal wrist flexion (p=0.0296) moments during pulling, which verified previously observed strategies. Finally, for both maximal and submaximal exertions, pulling was more sensitive to changes in off-axis forces compared to pushing which was more sensitive to postural flexibility. In conclusion, the underlying principles as to how and why off-axis forces change provides valuable knowledge to ergonomists so that they can more accurately predict force production in workplace design, ultimately reducing the potential for injury.

Delineating the extent of brine contamination in shallow groundwater systems using piezometers is costly and does not provide adequate data resolution. Direct-push (D-P) electrical conductivity (EC) profiling enables rapid in situ measurements of bulk soil EC (ECa) at the cm scale. Previous studies using D-P EC profiling to detect contaminant plumes have solely relied on ECa measurements, and where attempts were made to isolate pore-water salinity variations from changes in ECa they were accomplished using simple linear methods. In this study D-P EC profiling was used to define groundwater salinity distributions using an established soil conductance model and estimate the timing of groundwater contamination at a long-term potash mine in south-central Saskatchewan, Canada. The site was dominated by fine-grained postglacial and glacial sediments with known Na-K-Cl brine impacts resulting from mining activities. Coreholes (n=22) were drilled to 7.6-12.2 m below ground (mbg) to obtain continuous cores for detailed geologic descriptions and measurements of index parameters (n=522) below the water table. Pore-water EC (ECw) and Cl- results from squeezed core samples (n=142) at 12 locations were compared to ECa measurements collected using a D-P probe adjacent to each corehole. Measured ECw and pore-water Cl- results ranged from 1.94-55.1 mS/cm and 87-20,700 mg/L, respectively. In situ D-P EC values from logs collected adjacent to all 22 coreholes ranged from 2-8 mS/cm within the oxidized zone (5-6 mbg) and decreased to background values of 0.3-2 mS/cm within the underlying unoxidized zone. Significant linear ECa–ECw regressions established for four lithological groups (r2=0.78-0.95) were used with porosity and dry density measurements to generate high-resolution depth profiles of ECw from D-P EC measurements. A significant linear ECw–Cl regression (r2=0.92) further enabled the generation of pore-water Cldepth profiles from ECw predictions. Observed 1D vertical profiles of Cl-, ECw, and ECa at three locations were modeled. Results suggested solute transport can be described as diffusion-dominated below depths of 3-5 mbg and that groundwater contamination began shortly after the onset of mining. Based on the results attained, this method can generate high-resolution depth profiles of pore-water salinity that can be used to define the lateral and vertical extent of brine contamination, dominant solute transport mechanisms, and timing of groundwater contamination.

South Africa is in the throes of a skills crisis. This situation is seriously hampering the country's economic progress and global participation. This study focuses on the analysis of skills migration in South Africa, and specifically aims to provide a conceptual framework for better cognition of the skills situation in South Africa. The study is presented in a series of four articles with a final chapter that incorporates these articles in a cognitive unit and, therefore, provide a cognitive map to better understand skills migration in South Africa. Article one of the study provides an in–depth discussion on the serious shortage of skilled workers and its impact on the progress of the country. This crisis is largely due to the failure of the national education and training system to supply the economy with much needed skills required to support economic growth and job creation. The findings of this study indicated that there are various factors that are contributing to the skills shortages in the country. Some of the factors include: poor education standards, emigration, crime and HIV. It must be noted that these factors cannot be addressed overnight. Hence, this study emphasised the role that skilled foreign workers can play in alleviating the skills shortages in the country. The contribution of foreign workers could be viewed as a short to medium solution to the skills crisis. Finally, this study has confirmed the findings of similar studies undertaken by the Centre for Development and Enterprise that opening the doors to high–skilled immigration can only serve as a means of supplementing the skills pool and hence contributing to the economic growth of the country. In relation to the above, that is, a means to address the skills shortages, article two supported the view that a more expansive and robust policy approach to skills immigration can be part of the larger solution of addressing the skills shortages of the country. This would allow for economic progress and make South Africa globally competitive. Hence, the primary purpose of this article was to determine the effectiveness of South Africa's immigration policy to support skills immigration. Attempts to recruit foreign skills to work in South African firms is proving to be a challenge as there are a number of issues in South Africa's immigration policy that makes it restrictive for organisations when recruiting skilled foreign workers. The following are some of the consequences of this restrictive policy: due to major infrastructural growth and development during the 2010 period, there is tremendous strain on the construction industry as a result of shortage of engineers, quantity surveyors, technicians and architects. Problems in retaining skilled mining staff combined with insufficient new graduates and an aging workforce is affecting the South African industry. A dearth of engineering skills at Eskom has also contributed to the power crisis. Thus it could be concluded that South Africa's skills immigration policy is problematic and not helpful in addressing the skills shortages of the country. In addition and in relation to factors that are contributing to skills shortages in the country, article three of the study focused specifically on factors that either push or pull people into a country. Push factors are generally regarded as negative factors as they push people out of the country. These factors include affirmative action, which contributes to emigration of skilled individuals, crime, HIV, economic instability, poor health care and dissatisfaction with the political situation of the country. Pull or positive factors on the other hand draw skilled South Africans to a country. These factors include: attractive salary packages, early retirement within the education sector, an opportunity to gain international work experience, an improved lifestyle and variety of career choices. Certain immigrants are pulled to South Africa as they see it as offering them economic opportunities that are not available in their home country. However, these immigrants range largely from unskilled to a limited number of highly skilled workers. This is inadequate to address the skill shortages. Hence, this situation also points towards recruitment of skilled foreign workers as a short to medium term solution. The final article of the study confirms that skills shortage is a global phenomenon. As a result there is fierce competition amongst countries to attract skilled labour so as to alleviate these shortages and improve their competitive footing in the global economy. One major way that these countries strive to achieve their goal, is through promoting targeted skills immigration programmes to attract skilled workers. In order to alleviate these skills shortages and be part of the global economy, South Africa has to take lessons from these countries. Therefore, the main purpose of this article in the study was to indicate the advantages of having a competitive skills immigration policy. It also highlighted practices that make certain countries skills immigration programmes successful. In doing so, these suitable practices could be offered to policy makers so that they can make informed decisions on improving the skills immigration policy of the country. Finally, there is a general consensus that South Africa's policy on skills immigration is in need of radical review due to the fact that it is highly restrictive, bureaucratic, user–unfriendly and costly to administer. Moreover, it serves as an impediment for business and industry to recruit skilled foreign labour into the country as a result of excessive, and often, unnecessary regulations and procedures. As a consequence, South Africa tends to attract a higher proportion of unskilled and semi–skilled foreign workers when, in actual fact, it should be attracting highly skilled immigrants. / Thesis (Ph.D. (Business Administration))--North-West University, Potchefstroom Campus, 2011.

South Africa is in the throes of a skills crisis. This situation is seriously hampering the country's economic progress and global participation. This study focuses on the analysis of skills migration in South Africa, and specifically aims to provide a conceptual framework for better cognition of the skills situation in South Africa. The study is presented in a series of four articles with a final chapter that incorporates these articles in a cognitive unit and, therefore, provide a cognitive map to better understand skills migration in South Africa. Article one of the study provides an in–depth discussion on the serious shortage of skilled workers and its impact on the progress of the country. This crisis is largely due to the failure of the national education and training system to supply the economy with much needed skills required to support economic growth and job creation. The findings of this study indicated that there are various factors that are contributing to the skills shortages in the country. Some of the factors include: poor education standards, emigration, crime and HIV. It must be noted that these factors cannot be addressed overnight. Hence, this study emphasised the role that skilled foreign workers can play in alleviating the skills shortages in the country. The contribution of foreign workers could be viewed as a short to medium solution to the skills crisis. Finally, this study has confirmed the findings of similar studies undertaken by the Centre for Development and Enterprise that opening the doors to high–skilled immigration can only serve as a means of supplementing the skills pool and hence contributing to the economic growth of the country. In relation to the above, that is, a means to address the skills shortages, article two supported the view that a more expansive and robust policy approach to skills immigration can be part of the larger solution of addressing the skills shortages of the country. This would allow for economic progress and make South Africa globally competitive. Hence, the primary purpose of this article was to determine the effectiveness of South Africa's immigration policy to support skills immigration. Attempts to recruit foreign skills to work in South African firms is proving to be a challenge as there are a number of issues in South Africa's immigration policy that makes it restrictive for organisations when recruiting skilled foreign workers. The following are some of the consequences of this restrictive policy: due to major infrastructural growth and development during the 2010 period, there is tremendous strain on the construction industry as a result of shortage of engineers, quantity surveyors, technicians and architects. Problems in retaining skilled mining staff combined with insufficient new graduates and an aging workforce is affecting the South African industry. A dearth of engineering skills at Eskom has also contributed to the power crisis. Thus it could be concluded that South Africa's skills immigration policy is problematic and not helpful in addressing the skills shortages of the country. In addition and in relation to factors that are contributing to skills shortages in the country, article three of the study focused specifically on factors that either push or pull people into a country. Push factors are generally regarded as negative factors as they push people out of the country. These factors include affirmative action, which contributes to emigration of skilled individuals, crime, HIV, economic instability, poor health care and dissatisfaction with the political situation of the country. Pull or positive factors on the other hand draw skilled South Africans to a country. These factors include: attractive salary packages, early retirement within the education sector, an opportunity to gain international work experience, an improved lifestyle and variety of career choices. Certain immigrants are pulled to South Africa as they see it as offering them economic opportunities that are not available in their home country. However, these immigrants range largely from unskilled to a limited number of highly skilled workers. This is inadequate to address the skill shortages. Hence, this situation also points towards recruitment of skilled foreign workers as a short to medium term solution. The final article of the study confirms that skills shortage is a global phenomenon. As a result there is fierce competition amongst countries to attract skilled labour so as to alleviate these shortages and improve their competitive footing in the global economy. One major way that these countries strive to achieve their goal, is through promoting targeted skills immigration programmes to attract skilled workers. In order to alleviate these skills shortages and be part of the global economy, South Africa has to take lessons from these countries. Therefore, the main purpose of this article in the study was to indicate the advantages of having a competitive skills immigration policy. It also highlighted practices that make certain countries skills immigration programmes successful. In doing so, these suitable practices could be offered to policy makers so that they can make informed decisions on improving the skills immigration policy of the country. Finally, there is a general consensus that South Africa's policy on skills immigration is in need of radical review due to the fact that it is highly restrictive, bureaucratic, user–unfriendly and costly to administer. Moreover, it serves as an impediment for business and industry to recruit skilled foreign labour into the country as a result of excessive, and often, unnecessary regulations and procedures. As a consequence, South Africa tends to attract a higher proportion of unskilled and semi–skilled foreign workers when, in actual fact, it should be attracting highly skilled immigrants. / Thesis (Ph.D. (Business Administration))--North-West University, Potchefstroom Campus, 2011.

The aim of this research was to explore the travel motivations of Taiwanese tourists who visited Australia, their satisfactions, and destination loyalty, as well as examining the relationship between customer satisfaction, need satisfaction, and destination loyalty. This study is important because of the fact that the number of Taiwanese tourists to Australia has decreased since 1999; however, there have not been any academic studies to ascertain the travel motivations of Taiwanese group package tourists who visited Australia, their need satisfaction, and future intentions. Furthermore, the literature on tourist need satisfaction, customer satisfaction and loyalty has been categorised into discrete areas of study, with little integration of these three concepts in the tourism literature. Thus, the relationship between these concepts is an area of theoretical interest that has been examined in this study. To achieve the aims of the research, one research question and 11 hypotheses were developed. The research question specifically explored the travel motivations of the Taiwanese when visiting Australia. Two hypotheses were designed to test the differences between Taiwanese travel motivations and their need satisfaction, and the differences between travel motivation groups. In addition, nine hypotheses were used to examine the relationships between customer satisfaction, need satisfaction, and destination loyalty. A four-stage research methodology was used. Firstly, the study adopted a qualitative approach using focus group interviews of 33 participants to explore the motivations of Taiwanese group package tourists to Australia. Following the qualitative study, two pre tests including a pre and post survey were conducted in order to develop the scales for travel motivations, customer satisfaction, need satisfaction, and destination loyalty of Taiwanese tourists. Finally, a formal pre and post survey was administered. A pre and post survey design was used to consider the potential changes in tourist motivations after the trip. Cluster sampling was used to select the travel agencies, and five travel agencies agreed to participate in this research. The collection of data for the formal survey began in September 2005 and was completed at the end of February 2006. A total of 547 questionnaires were fully completed with a response rate of 72.9%. The validity and reliability of the various scales for push and pull motivations, destination attributes/services, group package tour services, perceived value, equity, emotion, overall need satisfaction, overall satisfaction, and destination loyalty were examined using exploratory and confirmatory factor analysis, as well as Cronbach’s alpha, and all scales were found to be satisfactory. A total of 17 push and 18 pull motivation items were also determined. Taiwanese tourists had the highest travel motivation scores for ‘travelling around the world’, and ‘having a comfortable trip’, and were attracted by certain attributes of Australia, such as the ‘sunshine and scenery’, and ‘a place to go for good value’. The differences between travel motivations and motivation satisfaction were examined using a paired sample t-test, and the hypothesis was partially supported. Based on the results of these t-tests, importance-performance analysis (IPA) was used to analyse the motivation satisfaction levels, and the results showed that the main travel motivations of Taiwanese travellers to Australia were generally satisfied after the trip, with the push motivation factor ‘having a comfortable trip’ and the pull motivation factor ‘sunshine and scenery’ scoring highest on the satisfaction scale. Factor-cluster analysis was further used to segment tourists in regard to their travel motivations. The results revealed that there were four different travel motivation groups. These groups were significantly different in terms of their customer satisfaction and destination loyalty. The importance level of travel motivations of ‘high motivation travellers’ before the trip was high compared to other groups and the customer satisfaction and destination loyalty were also high after the trip. Taiwanese tourists were generally satisfied with their trip to Australia; however, only two tourist groups: the ‘high motivation travellers’ and the ‘comfort/attraction seekers’ showed any interest in revisiting Australia in the future. The relationship between customer satisfaction, need satisfaction, and destination loyalty was also examined using multiple regression analysis. The results confirmed the hypotheses that customer satisfaction had a positive impact on need satisfaction; need satisfaction positively influenced overall need satisfaction; and overall need satisfaction and overall satisfaction both had a positive relationship with destination loyalty. This shows that tourist need satisfaction and customer satisfaction are related, and customer satisfaction is the antecedent of tourist need satisfaction. Furthermore, tourist need satisfaction is influenced by travel experiences, and destination loyalty is influenced by overall need satisfaction and overall satisfaction. This research has contributed to theory, methodology and to practice. A relationship between customer satisfaction, need satisfaction, and destination loyalty was found. As a result, this study has also successfully integrated the concepts of travel motivation, customer satisfaction, need satisfaction, and destination loyalty. A pre and post survey methodology was used in this research to obtain Taiwanese travellers’ original motivations and their satisfaction levels. Finally, the findings concerning the motivations of Taiwanese tourists to Australia, their need satisfaction, customer satisfaction, and destination loyalty have been found to be useful for tourism managers to assist them in making successful business decisions, improving services, and developing new promotional strategies to encourage Taiwanese visitors to travel to Australia.

Zugl.: Dortmund, Techn. Univ., Diss., 2008

The research presented in this thesis is to evaluate the feasibility of demountable shear connectors as an alternative to welded shear connectors in composite structures through push off tests and composite beam tests. Push off tests were conducted to examine the shear strength, stiffness and ductility of demountable shear connectors in composite structures. The experimental results showed that demountable shear connectors in composite structures have very similar shear capacity to welded shear connectors. The shear capacity was compared against the prediction methods used for the welded shear connections given in Eurocode 4 and AISC 360-10 and the methods used for bolted connections in Eurocode 3 and ACI 318-08. It was found that the AISC 360-10 and ACI 318-08 methods overestimated the shear capacity in some cases. The Eurocode method is conservative and can be utilised to predict the shear capacity of demountable connectors in composite structures. The experimental studies of two identical composite beams using demountable shear connectors and welded shear connectors showed very similar moment capacity. However, the specimen with demountable shear connectors was more ductile compared to the welded specimen. The experimental study suggests that the methods available in Eurocode 4 and BS 5950 for predicting moment capacity and mid span deflection can be adopted for composite beam with demountable shear connectors. In addition, a finite element analysis of push off test and beam test with demountable shear connectors was also conducted for parametric studies and results are used to evaluate the behaviour of composite structures.

La connaissance des conditions psychosociologiques dans lesquelles les entrepreneurs décident de la fin de leur carrière renvoie à des enjeux particulièrement cruciaux pour les chercheurs et les praticiens du conseil. Les conséquences de l’arrêt de l’activité entrepreneuriale sont en effet notables à la fois aux plans individuel, macro-économique car liés à la problématique de la cession-transmission de l’entreprise et sociaux au regard des emplois à préserver (Detienne, 2010). La finalité générale de cette thèse était d’éclairer les facteurs psychosociologiques complexes qui sous-tendent la décision du départ à la retraite dans la population des dirigeants propriétaires. Pour ce faire, le présent travail doctoral visait deux objectifs majeurs. Le premier était de développer un inventaire fiable permettant l’analyse précise de la nature et de la structure des raisons conduisant les entrepreneurs à prendre la décision de mettre fin à leur carrière professionnelle. Trois études distinctes portant sur 442 participants au total ont permis la création et la validation de l’Inventaire des Raisons du Processus Décisionnel du départ à la Retraite des Entrepreneurs (IRPDRE), à partir du modèle Push Pull Anti-push Anti-pull de Mullet, Dej, Lemaire, Raïff, & Barthorpe (2000). Le second objectif visé dans l’étude 4 portait sur le test auprès d’un échantillon de 271 participants d’un modèle des déterminants individuels de la perception des raisons sous-tendant le processus décisionnel de l’arrêt de la carrière chez les entrepreneurs. Cette modélisation incluait également l’examen des liens entre l’évaluation des diverses raisons et l’intention de partir à la retraite des entrepreneurs. Au final, les résultats obtenus dans ce programme de recherches ont permis de proposer un outil multidimensionnel fiable permettant d’évaluer finement la perception complexe des facteurs psychosociologiques à l’origine de la prise de décision du désengagement professionnel des entrepreneurs. Ils ont aussi conduit à une meilleure compréhension des différences interindividuelles lors de la prise de décision de fin de carrière dans cette population. / Understanding the psychosociological conditions of entrepreneurs’ decisions to retire is an important issue for researchers and practitioners. Indeed, the consequences of entrepreneurs’ decisions to retire are important at three levels: individual, macroeconomic in that their retirement is linked to the disposal and transfer of their business, and social in that it affects employment (Detienne, 2010). The overall purpose of this doctoral research was to analyze the psychosociological factors underlying the retirement decision in this specific population. The study had two main objectives. The first was to provide researchers and practitioners with an original and reliable self-report questionnaire to assess the nature and form of the reasons underlying the retirement decision process. Three studies, with a total of 442 participants, were conducted to develop and validate the Reasons for Entrepreneurs’ Retirement Decision Inventory (RERDI), based on the Push Pull Antipush Anti-pull view (Mullet, Dej, Lemaire, Raïff, & Barthorpe, 2000). A fourth study involving 271 participants was carried out to achieve the second objective, which was to test a model of individual determinants of the reasons underlying the retirement decision process. This model also examined the relationships between the evaluation of the reasons and the intention to retire. Finally, the results of these studies allow us to propose a multidimensional and reliable tool to assess in detail the complex perception of the psychosociological factors underlying entrepreneurs’ decisions to retire. The results also provide a better understanding of interindividual differences in this retirement decision.