• Journal of KSNVE
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• v.4 no.1
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• pp.23-31
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• 1994

When a shaft is misaligned, a high level of vibration is experienced. As a consequence, the system performance could be low with high level of noise generated. Even, a catastrophic damage of the rotating machinery may happen in the worst situation. The vibration caused by the shaft misalignment is not cured unless a correct alignment of the shaft is investigated. In this paper, a step by step approach for the turbine alignment has been demonstrated. It includes measurement tips of the coupling rim and face, calculation procedure of the bearing level, and the relevant values of the addition and subtration for shims in order to align the shaft level correctly. Then, as an application of the shaft alignment, the turbine system at the Pyung Tek focile electric power plant has been examined. Since the real system consists of high pressure, low pressure turbines and the generator, detailed alignment prolcedures of the multi stage shaft system has been demonstrated.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.842-847
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• 2005

Although there are many applications of Euclidean Voronoi diagram for spheres in a 3D space in various disciplines from sciences and engineering, it has not been studied as much as it deserves. In this paper, we present an edge-tracing algorithm to compute the Euclidean Voronoi diagram of 3-dimensional spheres in O(mn) in the worst-case, where m is the number of edges of Voronoi diagram and n is the number of spheres. After building blocks for the algorithm, we show an example of Voronoi diagram for atoms using actual protein data and discuss its applications for protein analysis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.8 no.1
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• pp.139-148
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• 2002

As the Busan harbor is getting susceptible to oil Pollution. the authors analyze the historical records of oil spill accidents and investigate the shoreline features. In addition. we evaluate the response capabilities and compute the required stockpiles of marine oil spill response with the worst case scenario in this area. As a result, it is shown that the recommendable oil spill response is to contain and mechanically recover all oils at sea surface in winter. while chemical dispersants can be used in summer with mechanical containment and recovery, and it is also found that off-shore booms of 3,000m and off-shore skimmers of 986MT/hour recovery rate should be stockpiled with 10,000∼60,000 liters of concentrate chemical dispersant and small amount of synthetic organic sorbents for possible use.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.21-25
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• 1986

Structure-borne noise due to forced vibration which is originated from subway operation and transmitted to buildings in order of rail-wood tie-concrete bed-structure-soil-building foundations-members of building results in social problem of environmental pollution. Moreover this becomes a serious problem because of the increment of surface traffic and subway operation made by meeting traffic system in crowded cities. Since subway is constructed along the principal road or through the residential area and as the worst case may be, building foundations is contact with top part of subway structure, it is possible that vibration resonance results in fatal damage of buildings. And, structure-borne vibration noise due to subway operation at late and early hours have the residents suffer from insonmia, restlessness and so on. Therefore, to satisfy the future need concerning the environmental protection, this report deals with the influence of structure-borne vibration noise on the basis of the characteristics of Seoul Subway System.

• Journal of electromagnetic engineering and science
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• v.16 no.4
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• pp.225-228
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• 2016

KRISS-V, a V-band millimeter-wave source module for a primary RF power standard and calibration system developed by the Korea Research Institute of Standards and Science is here presented. The output power of KRISS-V is several times higher than that of commercial amplifier/multiplier chains and is highly stable (the standard deviations of output power are less than 0.01% in the worst case). The spectral purity of KRISS-V is high enough to consider it a single-tone signal generator. We also added programmable attenuation capability to KRISS-V for remote power control. Moreover, the in-house source module is cost-effective and adaptable to various measurement schemes. The structure of the model as well as detailed component information are introduced so that it can be reproduced.

• Journal of Computing Science and Engineering
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• v.7 no.2
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• pp.89-98
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• 2013

This paper presents a complete survey of recent techniques that are applied in the field of real-time Java computing. It focuses on the issues that are especially important for hard real-time applications, which include time predictable garbage collection, worst-case execution time analysis of Java programs, real-time Java threads scheduling and compiler techniques designed for real-time purpose. It also evaluates experimental frameworks that can be used for researching real-time Java. This overview is expected to help researchers understand the state-of-the-art and advance the research in real-time Java computing.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.2060-2071
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• 2000

Scheduling parallel tasks, represented as a Directed Acyclic Graph (DAG) or task graph, on a multiprocessor system has been an important research area in the past decades. List scheduling algorithms assign priorities to a node or an edge in an input DAG, and then generate a schedule according to the assigned priorities. This appear proposes a list scheduling algorithms with effective method of priority assignments. The paper also analyzes the worst case performance and optimality condition for the proposed algorithm. The performance comparison study shows that the proposed algorithms outperforms existing scheduling algorithms especially for input DAGs with high communication overheads. The performance improvement over existing algorithms becomes larger as the input DAG becomes more dense and the level of parallelism in the DAG is increased.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.67-72
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• 2014

PURPOSES : This study focuses on conducting pavement rehabilitation for more deteriorated roads given a limited government budget. METHODS : Therefore, we apply a optimization programming model of the permutation algorithm used for rehabilitating more deteriorated pavement areas, which is subjected to the limited budget. RESULTS : The permutation algorithm was evaluated in terms of determining the maximized rehabilitation of deteriorated pavement areas, using the newly developed performance models such as fatigue cracking, rutting, international roughness index(IRI) through the surveying data from 2006 to 2012. When compared with a traditional model of the so-called worst-first sequence(WFS) method, the permutation algorithm worked better than the WFS method, resulting in covering more deteriorated pavement areas given the limited government budget. CONCLUSIONS : Through a case study, it could be concluded that the permutation algorithm provides more reliable results in terms of rehabilitating more deteriorated pavement areas given the limited budget.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1155-1160
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• 2007

This paper presents position error for the robot localization system using the ultrasonic wave. The distance between the receiver and a beacon can be computed by using the difference between times of flight. The distance information measured by ultrasonic wave has errors. The position is calculated by distances, and this error is caused by distance errors. The position error is different from receiver¡s position. And the position is also calculated by beacon location. This paper calculates worst case position error within measuring area, and finds beacons location to reduce the position error.

• International Journal of Automotive Technology
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• v.5 no.2
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• pp.115-122
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• 2004

Evaluation of active safety control systems usually relies heavily on field testing and is time-consuming and costly. Advances in computer simulations make it possible to perform exhaustive design trials and evaluations before field testing, and promise to dramatically reduce development cost and cycle time. In this paper, a comprehensive simulation-based evaluation procedure is proposed, which combines standard evaluation maneuvers, worst-case techniques, and a driver model for closed-loop path following evaluations. A vehicle dynamic controller (VDC) for a popular Sport Utility Vehicle is evaluated using the proposed procedure. Simulation results show that the proposed procedure can be used to assess the performance of the VDC under various conditions and provides valuable information for the re-design of the VDC.