• Journal of Family Resource Management and Policy Review
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• v.17 no.1
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• pp.241-263
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• 2013

Time pressure and financial burden have been reported as the main constraints on leisure participation. The purpose of this study was to explore a typology of leisure constraints, investigate the characteristics of leisure constraint types, and analyze the differences in leisure participation by the types of leisure constraints for married employees. The data source for this research was the 2009 Time Use Survey conducted by the Korea National Statistical Office (KNSO). Married employees aged 20 to 59 years completed 13,476 time diaries (7,984 for male, 5,492 for female), which were analyzed using chi-square, cluster analysis, and ANOVA analysis. Leisure constraints were classified into five types in two categories, working time per week and personal income for both males and females respectively. The three types for both males and females were time-income constraints, income constraints, and general constraints, with an additional type for men, $time^+$-income constraints, and an additional type for women, time constraint. The most common type was general constraints, for both males and females. Each type was further differentiated by the following socio-economic variables: age, educational level, job type, and weekly day-off. The study found that participation in study, sports, and religious activities varied with the types of leisure constraints.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.4
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• pp.12-21
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• 1992

Many real-time supporting features are used to execute real-time process in a time-constraints given. In this paper, The real-tiem resources management mechanism based time constraints which order resources supporting real-time processes blocked by the processes was proposed. This mechanism was all implemented and tested on the UNIX operating system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.1-13
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• 2005

For integrated transit networks operated with diverse transit modes, it is difficult to find related literatures on the provision of multiple travel time routes information. This study proposes a methodology on how to select K number of least time transit routes in the integrated transit network with two modes, bus and subway. In the Proposed method, three constraints usually (will be) encountered for decision by users-(1) service time constraints of travel modes, (2) maximum payment fare constraints under the integrated distance based fare system, and (3) maximum number of transfer constraints - are taken into consideration in the searched routes. The experimental studies shows that the proposed method properly provides K number of least time routes. In addition, it somehow proves that by combinatorially considering three constraints the proposed method can be evaluated as to enlarge the quality as well as the diversity of route information demanded by users.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.230-233
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• 1987

This paper addresses the identification of various constraints in time-varying obstacle avoidance for mechanical manipulators. The manipulator constraints include the smoothness constraint and torque constraint, while the environmental constraints include a motion priority, a traveling time constraint, a path constraint, and a collision constraint. The inherent difficulties in combining these constraints are discussed with a suggestion for the purpose of time-varying obstacle avoidance.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.175-185
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• 2005

The scheduling methods of the distributed real-time systems have been proposed. However, they have some weak points. They did not schedule both sporadic and periodic tasks and messages at the same time or did not consider the end-to-end constraints such as precedence relations between sporadic tasks. This means that system scheduling must guarantee the constraints of practical systems and be applicable to them. This paper proposes a new scheduling method that can be applied to more practical model of distributed real-time systems. System model consists of sporadic and periodic tasks with precedence relations and sporadic and periodic messages and has end-to-end constraints. The proposed method is based on a binary search-based period assignment algorithm, an end-to-end laxity-based priority assignment algorithm, and three kinds of schedulability analysis, node, network, and end-to-end schedulability analysis. In addition, this paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system, shows that existing scheduling methods such as Rate Monotonic scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints, and proposes an end-to-end laxity-based priority assignment algorithm.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.3
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• pp.159-170
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• 1992

The size of time constaints is the critical bottleneck of the Crew Scheduling Problem (CSP). This paper deals with a method to extract the minimum required time constraints by k-shortest path algorithm. These time constraints are added as the "insurance constraints" to avoid the unnecessary tree search, which are very time-consuming procedures, for the integer solutions. The computational results show that the problem size in LP formulation could be reduced by our method.

• ETRI Journal
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• v.29 no.2
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• pp.201-211
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• 2007

This paper focuses on the scheduling problem with the objective of maximizing system throughput, while guaranteeing long-term quality of service (QoS) constraints for non-realtime data users and short-term QoS constraints for realtime multimedia users in multiclass service high-speed uplink packet access (HSUPA) systems. After studying the feasible rate region for multiclass service HSUPA systems, we formulate this scheduling problem and propose a multi-constraints HSUPA opportunistic scheduling (MHOS) algorithm to solve this problem. The MHOS algorithm selects the optimal subset of users for transmission at each time slot to maximize system throughput, while guaranteeing the different constraints. The selection is made according to channel condition, feasible rate region, and user weights, which are adjusted by stochastic approximation algorithms to guarantee the different QoS constraints at different time scales. Simulation results show that the proposed MHOS algorithm guarantees QoS constraints, and achieves high system throughput.

• The Korean Journal of Community Living Science
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• v.22 no.4
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• pp.599-613
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• 2011

This study aimed to provide an efficient time management scheme for farmers by analysing how they experience time constraints in spending their time and understand time management. Firstly, farmers found that they didn't have enough time for farm keeping as a result of house work obligations. It was caused by excessive time for agricultural work. Thus, 93.7% of respondents recognized that ‘they were pressed for time' because there is relatively less time to spend for socio-cultural and physiological matters. In addition, 83.0% responded that they felt the pressure of something. Respondents who were in forties reduced their sleeping hours due to lack of time. The majority of people who were in the farmhouse doing controlled horticulture cannot enjoy their own time for leisure owing to a lack of time. Secondly, respondents under thirty-nine years of age were solving the problems of time constraints as prioritizing matters, planning handling time and utilizing household instruments. On the other hand, respondents who were in forties found the solution by reflecting on their conduct toward a time consumption plan, self-evaluation and received help from their family and/or neighbors. A group of respondents who had already graduated from college or higher education often reflected on their conduct and self-evaluated. Respondants who participatied in farmhouse controlled horticulture, generally took turns in managing their house work. For reducing farmers' time constraints and managing their time efficiently, they should standardize matters done repeatedly and also manage time by dividing work among family members. Furthermore, if a long-term time scheme such as more than a month is established and practiced, time constraints may be somewhat solved.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.275-278
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• 2001

TOC(Theory of Constraints) - the emphasis of this philosophy was on identifying and eliminating constraints(bottle-necks) in the system. TOC solves this and optimizes whole system by improving manufacturing constraints that limit system result. In this paper, it is shown that the concept of the "delayed differentiation" can be applied for enhancing the efficiency of the time buffer and thus reducing the of the time buffer.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1741-1751
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• 2007

The imprecise computation technique ensures that all time-critical tasks produce their results before their deadlines by trading off the quality of the results for the computation time requirements of the tasks. In the imprecise computation, most scheduling problems of satisfying both 0/1 constraints and timing constraints, while the total error is minimized, are NP-complete when the optional tasks have arbitrary processing times. In the previous studies, the reasonable strategies of scheduling tasks with the 0/1 constraints on uniprocessors and multiprocessors for minimizing the total error are proposed. But, these algorithms are all off-line algorithms. Then, in the on-line scheduling, NORA(No Off-line tasks and on-line tasks Ready upon Arrival) algorithm can find a schedule with the minimum total error. In NORA algorithm, EDF(Earliest Deadline First) strategy is adopted in the scheduling of optional tasks. On the other hand, for the task system with 0/1 constraints, NORA algorithm may not suitable any more for minimizing total error of the imprecise tasks. Therefore, in this paper, an on-line algorithm is proposed to minimize total error for the imprecise real-time task system with 0/1 constraints. This algorithm is suitable for the imprecise on-line system with 0/1 constraints. Next, to evaluate performance of this algorithm, a series of experiments are done. As a consequence of the performance comparison, it has been concluded that IOSMTE(Imprecise On-line Scheduling to Minimize Total Error) algorithm proposed in this paper outperforms LOF(Longest Optional First) strategy and SOF(Shortest Optional First) strategy for the most cases.