• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.297-299
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• 2006

Many distributed applications is developed in various environment such as operating system, software platform. So, they exhibit different types of system behavior, status, during the course of their operation. Each such behavior may have different functional and non-functional requirements. Therefore, many distributed application need to fault-tolerance solution. Personal robot provide various service or application. Because personal robot has many application or service, it need to fault-tolerance architecture. A flexible architecture is required to provide dependability. In this paper, it is suggested a fault-tolerant architecture for module-based personal robot with module fault-tolerance, service fault-tolerance.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.3
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• pp.47-57
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• 1992

The purpose of this paper is to improve the operation performance of unit-load Automated Guided Vehicles (AGV's) used as a carrier and mobile workstation in a flow-shop type flexible manufacturing system. An algorithm is developed to determine the optimal job sequence which minimizes the vehicle idle time on the line and the production makespan by the use of the entering interval and travel time between workcenters. An entering times of AGV's and the minimum number of AGV's required are calculated by optimal job sequence. When the numbe rof AGV's is limited, enterling times of AGV's are adjusted to maximize the efficient use of vehicles. A numerical example is given to illustrate the application of the algorithm.

• The Journal of Korea Robotics Society
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• v.4 no.3
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• pp.233-242
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• 2009

This paper briefly reviews the path planning methods that are applicable to the autonomous mobile robots for the military. Two distinct path search algorithms, $A^*$ and $D^*$ that are most popular and flexible in public applications, among those reviewed are coded and analyzed in terms of combat environment assessment factors called METT+TC for the area of operations. The results imply that it is important to consider the characteristics of defense acquisition process and the specific requirements of defense operation so that the successful technology development of the Robot products is directly linked to the defense procurement of Robot products.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.313-314
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• 2006

Indicating product quantity by real time can be benefit both worker and management. Worker can compare real product quantity with its target and can adjust working speed to match with goal. Therefore, so called JPH equipment developed to indicate target quantity of product. As a main processor PIC16F877 was used and FND display were used to indicate current time, elapsed time, JPH value and target amount of product. Values like JPH and starting time, etc. are can easily be set by $4{\times}4$ numeric keypad and display datum likes target amount of product, current time and elapsed time, etc are displayed on FND by RS232 serial transmit. The operation of JPH equipment are tested and verified through long term test and are proved acting properly on working conditions.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.159-165
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• 2001

The fundamental fluid mechanics associated with the rotation of a smooth plane disk enclosed within a cylindrical chamber have been studied experimentally. In order to acquire systematic information pertinent to this problem torque and friction loss data were obtained over a wide range of disk Reynolds numbers for axial clearance-disk radius ratio H/R from 0.025 to 0.2 and radial tip gap-disk radius ratio s/R from 0.021 to 0.105. Loss analysis of hard disk drive(HDD) is presented to describe the contribution of windage loss of a rotating disk. The minimum loss from factor of HDD can be obtained from this analysis at each operation conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.481-487
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• 1997

The development of transportation and construction equipment has required higher engine power and lower operation cost. The sound which the engine emits often degrade the performance of the whole system which adopts that engine. Specially the marine engine requires high restriction on the noise level for the customer's comfort and safety. The noise and vibration of Diesel engine must be carefully considered in the early design step. The double antivibration system is effective to increase the efficiency of antivibration, and the acoustic enclosure for reducing the noise level. 2 DOF model was effective to estimate the antivibration performance, which allows to determine the mass of the engine bed and the specification of the engine mount. The mass distribution of the enclosure system can be considered effectively by using the FEM model. The design contains structurally rigid engine bed by FEM, which is for reducing the influence of the flexible vibration, rubber mount selection as well as the acoustic enclosure design.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3955-3966
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• 2014

With the exponentially increasing Internet traffic and emergence of more versatile and heterogeneous applications, the design of datacenter networks (DCNs) is subject to unprecedented requirements for larger capacity and more flexible switching granularities. Envisioning Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) as a promising candidate for such a scenario, we motivate the use of O-OFDM as the underlying switching technology in order to provide sufficient switching capacity and elastic bandwidth allocation. For this purpose, this article reviews the recent progresses of DCN deployment and assesses the scenario where the O-OFDM transmission and switching technology is employed in the underlying transport plane. We discuss the key issues of the datacenter-oriented O-OFDM optical networks, and in particular, elaborate on a number of open issues and solutions including system interconnection architecture, routing and resource assignment, survivability, and energy-efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2249-2257
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• 1998

In this paper, we propose the enhanced priority control algorithm that adaptively controls the cell service ratio according to the relative cell occupancy ratio of buffer. The asynchronous transfer mode (ATM) provides the means to support various multimedia services in broadband networks. To support multimedia services, various data traffics of different priorities should be controlled effectively. And also it needs congestion control functions required in the netowrk to carry out the control operation. To accomplish this in a flexible and effective manner, priority classes for the different services ar ecommonly used. The proposed enhanced priority control mechanism have two service calsses of the delay sensitive class and the loss sensitive class. The simulation results show that te proposed control mechanism improves the QoS, the charateristics of cell loss probability and mean cell delay time, by selecting propeor relativ ecell occupancy ratio of buffer and the average arrival rate.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.439-443
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• 1987

This paper presents a method for constructing model of manufacturing processes for simulation and design of the discrete control logic. The models represent the discrete vent evolution of the system as well as features of the underlying continues processes, for applications such as discrete parts manufacture and assembly, the process is decomposed into operations and for each operation the required resources and associated discrete resource slates are Identified. The structure of the discrete-level control is modeled by modified Perti nets which are synthesized from single resource activity cycles. Construction of nets provides discrete control logic with guaranteed properties based on extended Petri nets theory, for illustration, the proposed method is applied to the high-level discrete control of a two-robotic assembly cell.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.600-602
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• 1997

The kalman filter which has good estimating capabilities by means of the recursive computation from the previously known of obtained data is usually used for the system estimation in the case of not being directly measurable. The best estimating technique is still open issues on the PWR reactor control system to increase operating contingencies and to predict the safety margins for safer reactor operation. This paper addressed its estimating technique using kalman filter for the more flexible reactor control and showed the reasonable approach for discretization of the continuos-time system for reduction of computation errors.