• The Journal of Korea Robotics Society
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• v.3 no.2
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• pp.106-111
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• 2008

This paper presents a decentralized coordination for a small-scale mobile robot teams performing a task through cooperation. Robot teams are required to generate and maintain various geometric patterns adapting to an environment and/or a task in many cooperative applications. In particular, all robots must continue to strive toward achieving the team's mission even if some members fail to perform their role. Toward this end, given the number of robots in a team, an effective coordination is investigated for decentralized formation control strategies. Specifically, all members are required first to reach agreement on their coordinate system and have an identifier (ID) for role assignment in a self-organizing way. Then, employing IDs on individual robots within a common coordinate system, a decentralized neighbor-referenced formation control is realized to generate, keep, and switch between different geometric shapes. This approach is verified using an in-house simulator and physical mobile robots. We detail and evaluate the formation control approach, whose common features include self-organization, robustness, and flexibility.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.4
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• pp.27-36
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• 1993

This paper proposes a shortest path allocation algorithm over the processors on the hypercube system based on the message passing techniques with the optimized module allocation. On multiprocessor systems, how to divide one task into multiple tasks efficiently is an important issue due to the hardness of the life cycle estimation of each process. To solve the life cycle discrepancies, the appropriate task assignment to each processor and the flexible communications among the processors are indispensible. With the concurrent program execution on hypercube systems, each process communicaties to others with the method of message passing. And, each processor has its own memory. The proposed algorithm generates a callable tree out of the module, assigns the weight factors, constructs the allocation graph, finds the shortest path allocation tree, and maps them with hypercube.

• Journal of Korea Multimedia Society
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• v.9 no.1
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• pp.119-126
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• 2006

The task scheduling in multiprocessor system is one of the key elements in the effective utilization of multiprocessor systems. The optimal assignment of tasks to multiprocessor is, in almost practical cases, an NP-hard problem. Consequently algorithms based on various modern heuristics have been proposed for practical reason. This paper proposes a new task scheduling algorithm using Genetic Algorithm which combines simulated annealing (GA+SA) in multiprocessor environment. In solution algorithms, the Genetic Algorithm (GA) and the simulated annealing (SA) are cooperatively used. In this method, the convergence of GA is improved by introducing the probability of SA as the criterion for acceptance of new trial solution. The objective of proposed scheduling algorithm is to minimize makespan. The effectiveness of the proposed algorithm is shown through simulation studies. In simulation studies, the result of proposed algorithm is better than that of any other algorithms.

• Korean Journal of Social Welfare Studies
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• v.42 no.4
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• pp.329-363
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• 2011

This study is on the influence of organizational climates on social workers' professionalism in Social Welfare Centers, based on measurements of the recognition levels provided by the organizational climates. I collected 570 samples from social workers who are presently working at social welfare centers, and analyzed the data using T-test, ANOVA and Hierarchical Regression Analysis. The results of this Study are: I researched the effect of organizational climates on the professional capability and ethical responsibility of social workers in the Social Welfare Centers. First, from theoretical considerations, I controlled for the general variables which affected the observed professional capability and ethical responsibility of social workers (Level 1). And then, I examined the explanatory results to see the effect of the organizational factors (Level 2). Through Hierarchical Regression Analysis, the level one analysis showed the effect of the general factors on professional capability (4.4 %) and ethical responsibility (3.3%). The level two analyses showed the added effect of the organizational factors on professional capability (21.4 %) and ethical responsibility (21.1%). By adding the organizational factors, the R2 of professional capability increases 17% and that of ethical responsibility increases to 17.8%. These results are statistically significant. The level two organizational factors significantly affecting professional capability were Autonomy, Supervision, Task Assignment, position and work place. Ethical responsibility was affected significantly by level two organizational subcategory factors of Autonomy, Supervision, Task Assignment, gender and education level and work place. Incentive didn't have any effect on the professional capability or ethical responsibility.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.109-116
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• 2004

This paper deals with data association using 3 sets of passive linear array sonars (PUS) geometrically positioned in a Y-shaped configuration, but fixed in an underwater environment. The data association problem is directly transformed into a 3-D assignment problem, which is known to be NP-hard. For generic passive sensors, it can be sotted using conventional algorithms, while it in PLAS becomes a formidable task due to the presence of bearing ambiguity. In particular, we proposed data association method robust to bearing measurements errors by incorporating frequency information and analyze a region of ghost problem by geometrical relation PUS and target. We analyzed the effectiveness of the proposed method by representative simulation in multi-target.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.7
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• pp.501-508
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• 2004

In this paper, a coordinated scheduling algorithm is proposed to reduce end-to-end delay in distributed control of systems. For the algorithm, the analysis of practical end-to-end delay in the worst case is performed priory with considering implementation of the systems. The end-to-end delay is composed of the delay caused by multi-task scheduling of operating systems, the delay caused by network communications, and the delay caused by asynchronous timing between operating systems and network communications. Through some simulation tests based on CAN(Controller Area Network), the proposed worst case end-to-end delay analysis is validated. Through the simulation tests, it is also shown that a real-time distributed control system designed to existing worst case delay cannot guarantee end-to-end time constraints. With the analysis, a coordinated scheduling algorithm is proposed here. The coordinated scheduling algorithm is focused on the reduction of the delay caused by asynchronous timing between operating systems and network communications. Online deadline assignment strategy is proposed for the scheduling. The performance enhancement of the distributed control systems by the scheduling algorithm is shown through simulation tests.

• Journal of Convergence for Information Technology
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• v.11 no.3
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• pp.174-184
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• 2021

The present study intends to understand how multimodality can be implemented in a content course curriculum and how students perceive multimodal tasks. Twenty-eight students majoring in English were engaged in a digital storytelling assignment as a part of the content curriculum. Findings from the questionnaire and reflective essays that investigated students perceptions of digital storytelling showed that students felt that the assignment helped them engage in the task and felt motivated. In comparison to traditional writing tasks, students perceived digital storytelling to be more engaging and motivating, but felt that the assignment required more mental effort and caused more anxiety. By supporting students to explore technology and implement multimodal aspects in the learning process, digital storytelling can encourage engagement and autonomous learning to create meaningful works that are purposeful and enjoyable.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.69-75
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• 2018

Efficiency of Process in manufacturing industry is a critical factor to connect directly to competitiveness of product. In particular, due to FTAs with various worlds around the world, the domestic and overseas manufacturing industries are facing intense competitions, and it requires elaborate task management system for shortening production time. This study aims at seeking how to raise efficiency of manufacturing process, using motion analysis solution. When improving the process of manufacturing after verifying optimization using motion analysis solution, it can save costs for additional process, modification, or supplement. It can also deduce practical effect to improve productivity of companies. It is expected that the study will contribute to improve wastes in the work field and task assignment efficiency, to shorten time replacing equipment, to measure standard time, and to standardize task system.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.5
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• pp.442-449
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• 2013

In this paper, a simulation system based on X-Plane and MATLAB/Simulink for multiple UAVs is presented. For the conceptual design of this proposed system, a hierarchical system architecture for multiple UAVs is presented. This architecture has object-oriented data structure which consists of three objects (UAV status, mission and task, and environment) and a hierarchy consisting of four layers (decision making layer, task assignment layer, path and motion planning layer, and collision avoidance layer) is also proposed. In addition, this paper shows a implementation of simulation system based on the proposed system architecture using X-Plane and MATLAB/Simulink. The result of simulation from the developed system in this paper validate capability of application for multiple UAVs in real environment.

• ETRI Journal
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• v.29 no.3
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• pp.270-280
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• 2007

In Linux, real-time tasks are supported by separating real-time task priorities from non-real-time task priorities. However, this separation of priority ranges may not be effective when real-time tasks make the system calls that are taken care of by the kernel threads. Thus, Linux is considered a soft real-time system. Moreover, kernel threads are configured to have static priorities for throughputs. The static assignment of priorities to kernel threads causes trouble for real-time tasks when real-time tasks require kernel threads to be invoked to handle the system calls because kernel threads do not discriminate between real-time and non-real-time tasks. We present a dynamic kernel thread scheduling mechanism with weighted average priority inheritance protocol (PIP), a variation of the PIP. The scheduling algorithm assigns proper priorities to kernel threads at runtime by monitoring the activities of user-level real-time tasks. Experimental results show that the algorithms can greatly improve the unexpected execution latency of real-time tasks.