• Journal of the Korean Vacuum Society
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• v.18 no.6
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• pp.418-425
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• 2009

To get the stable and optimized proton beam in the KIRAMS-13 cyclotron which installed in the regional cyclotron center, it is necessary to measure the transverse profile of proton beam. Beam Induced Fluorescence monitor is one of the non-destructive methods to measure the beam profiles, and it has many advantages such as a simple structure, real-time measurement, and minimum energy loss. The objective of this research is the design and development of Beam Induced Fluorescence monitor to measure the proton beam profiles in the KIRAMS-13 cyclotron.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.13-19
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• 2015

The wood pellet is standardized of woody type fuel which of small cylindrical shape that is produced compress wood remnants in process of woody processing. The pellet is critical energy which expects to increase of the amount used in future. It consumes fuel which of home, common facilities stove and boiler, district heating, and CHP, etc. This study was to develop a movable pellet manufacturing equipment that can be mounted on a truck. The pellet production volume is approximately 309kg per hour, daily output is about 2ton. One days work based on the expected revenue of approximately \268,000 feasibility is considered sufficient.

• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.499-506
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• 2005

A hash chain is a structure organized by hash function with high speed in computation. Systems using the hash chain are using extensively in various cryptography applications such as one-time passwords, server-supported signatures and micropayments. However, the most hash chain based on the system using pre-paid method provides anonymity but has the problem to increase payment cost. In this paper, we propose a new hash chain based on the micropayment system to keep user anonymity safe through blind signature in the withdrawal process of the root value without disclosing privacy information, and to improve efficiency by using secret key instead of public key in the system without the role of certificate.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.29-33
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• 2019

Recently, due to the rapid improvement of communication technologies as well as the easy production of video contents, IPTV is becoming increasingly popular. Meanwhile, as the number of IPTV channels increases rapidly, much time is required for finding the user's desired channel. This paper discusses and analyzes the effectiveness of reducing IPTV channel searching delays by using memory management techniques of computer systems. Specifically, this paper introduces how memory management techniques such as memory replacement, prefetching, and caching techniques can be adopted in IPTV channel searching interfaces by mapping between the two problems and discusses the effectiveness of the techniques.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1609-1611
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• 2001

A large cross-section pulsed electron beam generator of cold cathode type has been developed for industrial applications, for example, waste water cleaning, flue gas cleaning, and pasteurization etc. The operational principle is based on the emission of secondary electrons from cold cathode when ions in the plasma hit the cathode, which are accelerated toward exit window by the gradient of an electric potential. The conventional electron beam generators need an electron scanning beam because the small cross section thermal electron emitter is used. The electron beam of large cross-section pulsed electron beam generator do not need to be scanned over target material because the beam cross section is large by 300$cm^2$. We have fabricated the large cross-sectional pulsed electron beam generator with the peak energy of 200keV and beam diameter of 200mm and obtained the large area electron beam in the air. The electron beam current has been investigated as a function of accelerating voltage, glow discharge current, helium pressure, distance from the exit window and radial distribution in front of the exit window.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.225-227
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• 2005

The in-core neutron Flux Mapping System in a pressurized water reactor yields information on the neutron flux distribution in the reactor core at selected core locations by means of movable detectors. The obtained data are used to verify the reactor core design parameters. The detector cables run through guide tubes(thimbles), and typically thirty-six to fifty-eight thimbles are allocated in the reactor depending on the number of fuel assemblies. These thimbles are inserted into nuclear fuel assemblies through conduits connected from the bottom of the reactor vessel to a seal table. During the plant refueling outage period, the thimbles are withdrawn up to 4m from the seal table, the height of a nuclear fuel. In spite of their importance, however, the thimble handling work has been performed by only human operators. In addition, its efficiency is very low due to narrow working environments on the seal table, thereby resulting in the excessive radiation exposure of maintenance personnel. To solve these problems, a new thimble handling equipment for in-core flux mapping system was developed, and we confirmed its effectiveness through experiments.

• Journal of the Korea Computer Graphics Society
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• v.18 no.4
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• pp.25-34
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• 2012

This paper presents a real-time GPU (graphics processing unit) ray casting scheme for rendering isosurfaces of BCC (body-centered cubic) volume datasets. A quartic spline field is built using the 7-direction box-spline filter accompanied with a quasi-interpolation prefilter. To obtain an interactive rendering speed on the graphics hardware, the shader code was optimized to avoid lookup table and conditional branches and to minimize data fetch overhead. Compared to previous implementations, our work outperforms the comparable one by more than 20% and the rendering quality is superior than others.

• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.225-232
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• 2015

The control element drive mechanism (CEDM) is an electro-mechanical device to control reactivity of the nuclear reactor. The conventional CEDM was installed on a nozzle of the reactor vessel closure head as an ex-vessel type. However, there have been demands for an in-vessel CEDM to fundamentally eliminate the rod ejection accident. Conceptual design of the in-vessel CEDM, which was developed based on the existing technology of the ex-vessel CEDM, is introduced in this paper.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.2
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• pp.105-111
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• 2005

In sheet metal forming, drawbeads are often used to control uneven material flow, which may cause defects such as wrinkles, fractures, surface distortion and springback. Appropriate setting and adjusting of the drawbead force is one of the most important parameters in sheet forming process control. Therefore in this study, drawbead test was performed at various bead surface treatment conditions to clarify the frictional characteristics between sheet and drawbead. Furthermore, the differences in drawing force between circular and rectangular shape beads have also been measured to estimate the effectiveness of bead shape on the material flow control. The results show that drawing and friction characteristic were strongly influenced by surface treatments of bead and bead shapes.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.3
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• pp.307-312
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• 2001

Ultrasonic signals from Charpy impact test specimen have been analyzed in order to evaluate the integrity of reactor pressure vessel. Base and weld metal that were extracted from reactor vessel doting plant outages according to the schedule of the surveillance test required by the related regulations have been used and the ultrasonic test parameters including velocity, attenuation, etc. showed a close correlations with the amount of neutron irradiation for base metal, relatively homogeneous materials. This result showed certain possibility where a nondestructive method could be used to predict the fluence of the Irradiation due to neutron in nuclear reactor vessel materials.