• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.463-467
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• 2003

This part of ISO 1940 covers the following: a) identification of errors in the balancing process of rigid rotors: b) assessment of errors: c) guidelines for taking into account: d) the evaluation of residual unbalance in two correction planes. Detailed consideration of errors associated with the determination of residual unbalance is covered in the first part of ISO 1940.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2002.03b
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• pp.153-159
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• 2002

This study mainly concentrates on the development of a land information management system to manage the land related information in an effective way for the water-pollutant buffering zone, which was established to sustain better quality of the drinking water over the upper part of the Han river. For developing such system, a procedure was implemented covering user requirement analysis, system design, spatial DB design, and coding. DB linkage with affiliated institutes and cadastral DB updating were proposed as the part of the efforts to enhance the applicability of the system. In addition to that, modularization was adopted for more efficient and cost-effective system development.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.101-110
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• 2011

With the deployment of broadband networking technology, many clients are enabled to receive various Video on Demand (VoD) services. To support many clients, the network should be designed by considering the following factors: viewer's waiting time, buffer requirement at each client, number of channel required for video delivery, and video segmentation complexity. Among the currently available VoD service approaches, the Polyharmonic and Staircase broadcasting approaches show best performance with respect to each viewer's waiting time and buffer requirement, respectively. However, these approaches have the problem of dividing a video into too many segments, which causes very many channels to be managed and used at a time. To overcome this problem, we propose Polyharmonic-Staircase-Staggered (PSS) broadcasting approach that uses the Polyharmonic and Staircase approaches for the head part transmission and the Staggered approach for the tail part transmission. It is simple and bandwidth efficient. The numerical results demonstrate that our approach shows viewer's waiting time is comparable to that in the Harmonic approach with a slight increase in the bandwidth requirement, and saves the buffer requirement by about 60\% compared to the Harmonic broadcasting approach by simply adjusting the video partitioning coefficient factor. More importantly, our approach shows the best performance in terms of the number of segments and the number of channels managed and used simultaneously, which is a critical factor in real operation of VoD services. Lastly, we present how to configure the system adaptively according to the video partitioning coefficient.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.69
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• pp.1-12
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• 2001

In this paper, the consumable concurred spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the operational availability maximization problem with any given fund limitation. the that the failure of a part follows a Poisson process and part failure rate is constant in spite of the decrease of number of equipments during operational period, an analytical method is developed to obtain spare part requirements using the generalized Lagrange multipliers method, The numerical examples show that analytic solution is mostly equal to the realistic solution obtained from simulation regardless of assumptions about part failure rate. It is expected that the analytical method developed in the paper can be effectively used to make a budget for provisioning the concurrent spare parts of newly procured equipment system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.207-212
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• 2017

Korean civil airworthiness requirements of powerplant system are regulated on KAS Part 23 and Part 33. These are equivalent to FAR Part 23, Part 33 of FAA and CS-23, CS-E of EASA. FAA and EASA rewrites entire airworthiness requirements for the small airplane. It changed current 'prescriptive regulation' into 'performance-based regulation' which makes the object of safety performance. Powerplant requirements are also changed extensively by these concept revolution. In accordance with reorganization, we studied new powerplant system requirements of FAR Part 23 and proposed ideal direction to rewrite of Korean Airworthiness Standard rewrite.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.1
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• pp.71-85
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• 2001

This paper considers a cost model for a U-shaped manufacturing cell formation which incorporates a required number of machines and various material flows together under multi-part multi-cell environment. The model is required to satisfy both the specified operation sequence of each part and the total part demand volume, which are considered to derive material handling cost in U-shaped flow line cells. In the model several cost-incurring factors including set-up for batch change-over, processing time for operations of each part, and machine failures are also considered in association with processing load and capacity of each cell. Moreover, a heuristic for a good machine layout in each cell is newly proposed based on the material handling cost of each alternative sequence layout. These all are put together to present an efficient heuristic for the U-shaped independent-cell formation problem, numerical problems are solved to illustrate the algorithm.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.51-58
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• 2006

In rapid prototyping, the optimal part orientation during fabrication is critical as it can improve part accuracy, minimize the requirement for supports and reduce the production time. Through investigating the geometric issues of STL model and process planning of RPM, This paper establishes optimizing model based on the considerations of staircase effect, support area and production time. The general satisfactory degree function is constructed employing the multi-objective optimization theory based on the general satisfactory degree principle. The best part-building orientation is obtained by solving the function employing generic algorithm. Experiment shows that the methods can effective resolve the part-building orientation in RP.

• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.15-22
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• 2013

The conformity of propulsion system need to be evaluated thorough the flight test because it is an important part of the airplane to ensure the flight safety. In the small airplane development, the flight test according to KAS(Korean Airworthiness Standards) Part 23 is one of the ways to verify compliance in terms of satisfactory aircraft/engine/propeller integration. This thesis introduces means of verifying the compliance and test requirement of KAS Part 23 for the conformity of the propulsion system in small airplane. It also describes procedures and methods of propulsion system flight test through KC-100 airplane project.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.991-996
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• 2001

It is well known that there are two experimental errors on acoustic decay measurements. One is due to the influence of the band pass filter the other one is that of an averaging device. In this paper the influence of the filter is in detail investigated. To minimize the influence of filter, the product of the filter bandwidth Β (3㏈ bandwidth) and the reverberation time T$\sub$60/ of the room under test is at least 16. Moreover, if the initial part of an acoustic decay curve is important, the strong requirement, i.e. BT$\sub$60/＞ 64, must be satisfied. In this paper, the wavelet filter bank instead of the band pass filter bank is applied to obtain an acoustic decay curve. As results, the influence of filter is reduced and then the value of BT$\sub$60/ required for obtaining an acceptable decay curve is at least 4. The strong requirement for the initial part of a decay curve is also replaced by the BT$\sub$60/＞ 16 instead of BT$\sub$60/＞ 64.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.1
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• pp.123-140
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• 1997

In this paper we consider closed flow line systems with samploing inspections. The total number of parts in the system is assumed to be N. The processings carried out of each station do not always meet the requirement of quality. Therefore, upon completion of its processing at each station, a part is inspected to determine whether the processings meet the requirement of quality or not. We assume that inspection are done on a random basis. If a part is found to be defective by an inspection, it is fed back to the apropriate station. Two different cases will be considered in this study : a three-station flow line system with infinite buffers and a two-station flow line system with finite buffers. For each case, we will develop an exact method to obtain the performance measures such as throughput, machinen utilization, average outgoing quality and manufacturing lead time. For the case of the two-station flow line system ith finite buffers, we will also develop an approximation method using a stage-aggregation technique. Then using buffers, we will also develop an approximation method using a stage-aggregation technique. Then using these results, we will try to find an optimal inspection policy which maximizes the expected net profit under a certain cost structure. Although we present the results only for the two or three station flow line system in this paper, the results obtained in this paper can be extended easily to the system which consists of more than two or three stations.