• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.1055-1058
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• 2005

In the ACPF(Advanced spent nuclear fuel Conditioning Process Facility), the spent fuel pellets which are highly radioactive materials are separated with its clad and are fed into the next conditioning process. For this, at the other facility called PIEF(Post Irradiation Examination Facility) a spent fuel rod, 3.5 m long, is cut by 25 cm long which is suitable length fur the decladding process. These rod-cuts are packed into the capsule and are moved to the ACPF. Once the capsule is unloaded in the ACPF, the rod-cut is taken out one-by-one from the capsule and installed on the decladding device. In these processes, the crushed spent fuel pellet can be scattered inside the facilities and thus it contaminate the hot cell. In this paper, we developed the specially designed capsule which prevents the pellets scattering and remarkably reduces the leading and unloading time of the rod-cuts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.224-230
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• 2005

In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience due to cleaning process. This paper introduces a new rapid manufacturing process called Rapid Heat Ablation process (RHA) using the rotary hot tool to overcome limitations of traditional machining process. The rotary hot tool to satisfy requirements of RHA process is designed and produced. In order to examine relationships between kerfwidth and process parameters such as heat input, speed of tool and speed of revolution, experiments were carried out. In addition, relationship between the kerfwidth and the effective heat input was obtained. Based on the experimental results, double-curved shape was ablated to show the validity of proposed process. In the procedure, the rough cut and fine cut were performed according to the conditions of process parameters without tool change process. The practicality and effectiveness of the proposed process have been verified through ablation of three-dimensional shape.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.46-52
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• 1995

This paper proposes methodologies for the development of radiation thermometer using InSb photo-detector of which spectral sensitivity is excellent over the wave length range of 2 .mu. m .approx. 5 .mu. m. The proposed radiation thermometer has broad measurement range from normal to high, up to more than 1000 .deg. C, with high accuracy, and can measure temperature on the material surface or heat emission noncontactely with high speed. Optical system was consisted of two convex lens with foruslength of 15.2mm for infrared lay focusing, Ge filter to cut the short wave length components and sapphire filter to cut the long wave length components. The cold shielded was installed in the whole surface of the light-absorbing element to remove the error- mometer, calibration using black body furnace which has temperature range of 90 .deg. C .approx. 1100 .deg. C was carried out, and temperature calaibration curve was obtained by exponential function curvefitting. The result shows maximum error less than 0.24%(640K .+-. 1.6K) over the measurement range of 90 .deg. C .approx. 700 .deg. C, and from this result the usefulness of the developed thermometer has been confirmed.

• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.269-275
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• 1997

Wind tunnel test results and their interpretations, which were performed to study the aerodynamic stability of tower of self-anchored suspension bridge, are presented in this paper. Tower and full models were tested under smooth and turbulent flow conditions. In the case of the tower with inclined two columns, the vibration due to wakes were occurred at wide velocity zone because the wakes with various frequencies were generated by inclined upstream column. It has to be emphasized that the vibration characteristics of the tower in the self-anchored suspension bridge may be very sensitive to the longitudinal boundary conditions of the girder at the supports. Because of the two natural frequency of the tower, out-of-plane bending and torsional, were not well separated, coupled motions were observed in a wide range of wind velocity. The effectiveness of corner cut, countermeasure to reduce the tower vibrations, was also studied. It has been found that 1:10, comer cut size to column width, may be the most effective ratio for reducing the vibrations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.3
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• pp.30-36
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• 2008

The multimedia that is characterized by multi-media, multi-features, multi-representations, huge volume, and varieties, is rapidly spreading out due to the increasing of application domains. Thus, it is urgently needed to develop a multimedia information system that can retrieve the needed information rapidly and accurately from the huge amount of multimedia data. For the content-based retrieval of moving picture, picture information is generally used. It is generally used when video is segmented. Through that, it can be a structural video browsing. The tasking that divides video to shot is called video segmentation, and detecting the cut for video segmentation is called cut detection. The goal of this paper is to divide moving picture using HMMD(Hue-Mar-Min-Diff) color model and edge histogram descriptor among the MPEG-7 visual descriptors. HMMD color model is more familiar to human's perception than the other color spaces. Finally, the proposed retrieval system is implemented as hardware.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.213-223
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• 2016

Traffic jams occur frequently due to the dense populations of cities. Accordingly, the discomfort of citizens has increased. In order to minimize traffic inconveniences, various public transportation facilities have been suggested. In this paper, for the economical construction of a near-surface railway system, the design of a trench shield is developed and a review of its applicability is done by creating and testing trench shield equipment on a small scale. The trench shield consists of an excavation part, a shield part and an advancement part. To examine the applicability of the trench shield, a laboratory test is carried out. The results of the laboratory test confirm the possibility of reducing the construction time at open-cut construction sites through the excavation of the trench shield. Although the laboratory test is an indoor and relatively small-scale experiment, it is considered to be possible to secure a construction speed of 3m/day when the trench shield equipment is used.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.589-597
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• 2000

This paper deals with the basic design of the traction motor(TM) by performing the train performance simulation(TPS). The TPS, considering min condition, provides some important information about selecting the latins of TM such as current, power and frequency, etc. Especially, calculating the current flowing into the TM by the TPS in the situation of normal condition and M-car cut out respectively, we can inspect whether the TM endures thermally under the contingency or not. This paper reviews the tractive effort of the train to meet the demands of consumer and then designs the TM electrically. finally, performing the TPS under emergency condition, it checks the thermal capacity of the TM to insure the justice of the TM under construction.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2007.10a
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• pp.63-79
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• 2007

Several remedial works were attempted to stabilize the collapsed area of the inlet slopes of diversion tunnel, but prevention of any further movement was being only carried out at beginning stage by filling the area with aggregates and rock debris, after several cracks had been initiated and developed around the area. The extra specialty developed folding zone is consisted with highly weathered Greywacke and Black shale. The suggested solution is to improve the properties of the rock mass of failed area by choosing the optimum level of reinforcement through the increment of slope rock support design so as to control the movement of slopes during the re-excavation. The Bakun hydroelectric project includes the construction of a hydroelectric power plant with an installed capacity of 2,520MW and a power transmission system connecting to the existing transmission networks in Sarawak and Western Malaysia. The power station will consist of a 210m height Concrete Faced Rockfill Dam. During the construction of the dam and the power facilities the Balui River has to be diverted of the tunnels is 12m and the tunnel width is 16m at the portal area. This paper describes the stability analysis and design methods for the open cut rock slopes in the inlet area of the diversion tunnels. The geotechnical parameters employed in stability calculations were given as a function of four defined Rock Mass Type (RMT) which were based on RMR system from Bieniawski. The stability calculations procedure of the rock slopes are divided into two stages. In the first stage, it is calculated for the stability of each "global" slope without any rock support and shotcrete system. In the second stage, it is calculated for each "local" slope stability with berms and supported with rock bolts and shotcrete. The monitoring instrumentation was performed continuously and some of the design modification was carried out in order to increase the safety of failed area based on the unforeseen geological risks during the open cut excavation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9C
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• pp.1269-1278
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• 2004

While the management of digital contents is getting more and more important, many researchers have studied about scene change detection algorithms to reduce similar scenes in the video contents and to efficiently summarize video data. The algorithms using histogram and pixel information are found out as being sensitive to light changes and motion. Therefore, visual rhythm gets used in recent work to solve this problem, which shows some characteristics of scenes and requires even less computational power. In this paper, a new scene detection algorithm using visual rhythm by direction is proposed. The proposed algorithm needs less computational power and is able to keep good performance even in the scenes with motion. Experimental results show the performance improvement of about 30% comparing with conventional methods with histogram. They also show that the proposed algorithm is able to keep the same performance even to music video contents with lots of motion.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.6
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• pp.87-93
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• 1994

This paper describes on the establishment of an optimal internal grinding conditions for the purpose of improving the grinding efficiency against to the high-speed grinding. Through the fundamental grinding tests for the brittle and hardened material, we are concluded that high-speed internal grinding is effective to improve the grinding accuracy as well as the grinding efficiency. The obtained results are as follows: (1) Under the speed ratio $(V_w/V_g)$ is constant, it is possible to increase the grinding efficiency with satifying the constraint conditions. (2) Increasing the wheel velocity, surface roughness and out-roundness are improved. (3) Under the wheel depth of cut is constant and increasing the speed ratio, workpiece residual stress is decreased. The described method, in this paper, is capable of determining the optimum internal grinding conditions taking into account some constraint conditions, and practical algorithm for optimum internal grinding conditions are presented.