• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2572-2580
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• 2020

Emerging gamma ray detection applications that utilize neutron-based interrogation result in the prompt emission of high-energy (>2 MeV) gamma-rays. Rapid imaging is enabled by scintillators that possess high density, high atomic number, and excellent energy resolution. In this paper, we evaluate the bright (50,000 photons/MeV) oxide scintillator, cerium-doped Gd₂Al₂Ga₃O₁₂ (GAGG(Ce)). A silicon photomultiplier (SiPM) array is coupled to a GAGG(Ce) scintillator array (12 × 12 pixels) and integrated into a coded-aperture based gamma-ray imaging system. A resistor-based symmetric charge division circuit was used reduce the multiplicity of the analog outputs from 144 to 4. The developed system exhibits 9.1%, 8.3%, and 8.0% FWHM energy resolutions at 511 keV, 662 keV, and 1173.2 keV, respectively. In addition, a pixel-identification resolution of 602 ㎛ FWHM was obtained from the GAGG(Ce) scintillator array.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.288-292
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• 2010

Recently, in energy storage system, the EDLC is paid attention as a new environmentally friendly energy storage element. This capacitor has higher energy density than the electrolytic capacitor. Also, this capacitor has a lot of advantage such as no maintenance, longer life cycle and faster charge-discharge time than the battery system. But the EDLC must have a each charge-discharge controller to effectively control, an energy design method circuit to use effectively energy, and several compensation techniques to control a optimal operating. In this respect, this study suggests major parameters to effectively represent the characteristics of EDLC, the measurement methods of those parameters have been investigated with experiments, and the interpretation about the buck/boost DC/DC converter for the operation of EDLC.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.117-118
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• 2013

Recent global warming to the promotion of electric vehicles (EV), plug-in hybrid (PEV), including the next generation of cars and solar power, wind power and other renewable energy, and next-generation power grid (smart grid) are getting attention. In addition, the system utilizes the battery life in the industry and the convenience of a variety of social systems, economics, environmental impact, and the inherent potential to change significantly, and you can not walk into a next-generation industrial strategy and the need increases more and more present, and its early commercialization In order to do this, as well as a key energy source, the battery charger for charging efficiency technologies is essential. In this paper, fast charge multiple battery modules and optional modules that can charge distribution charge will be introduced.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.60-66
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• 2019

This study aims to develop and manufacture a device for inspecting impurities in a sealed aluminum container using an X-ray technique. Two X-ray oscillators and detectors are used to detect the entire sample. The stage for sample movement was fabricated using two high-voltage generators and X-ray detectors arranged diagonally. In addition, the high-voltage generator is composed of a vacuum tube, a high-voltage generator, and circulating oil for cooling. It includes a control unit for controlling other equipment, a power supply unit, and a video output unit; the most important part of the X-ray is the X-ray generation part. In this study, a flat panel was used along with the aim of developing the detector part. In particular, the development of the scintillator introduced in this study is a primary focus. The developed scintillator can be combined with a lens and can then be assembled with a charge coupled device (CCD) sensor.

• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.75-81
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• 2004

The port developments in Korea have been achieved by government because port needs large scale of funds for development and is recognized as SOC to be supplied by government. But this kind of policy has met budgetary problem to cope with rapidly increasing demands of port facilities. Thus in recent years, Korean government has tried to induce commercial capital to the construction of port facilities and allow port company to operate the facilities commercially for given period enough to compensate the investment. At present, several private ports are under construction and some will be opened in the near future. But on this stage, it is expected some problems for the reasonable port operation. This paper tried to scan and to analyze the current situation and also to find proper solutions.

• Journal of Korean Port Research
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• v.3 no.1
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• pp.3-33
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• 1989

The amount of the Korean export & import in 1987 reached $88.3 billion which was 1.75% of the total world trade and the proportion of foreign dependence to G.N.P was 74.5%. From these facts, we can infer that the development of national economy is largely dependent upon trade. Therefore the role of transportation, especially Ocean transportation, as a basis of economic development through trade is one of the main factors that can not be passed over. Here, We can define that a port as a subsystem of transportation determines the efficiency of the total transportation system. Thus, the purpose of this paper is to contribute in improvement of the efficiency in port, reinforcement of the international competitiveness for exporting goods by the analysis of the cargo handling charges. In order to do this, this paper deals the case of B.C.T.O.C. Furthermore, this study gives some important informations related to the level of tariffs for establishing an autonomous port administration. The Summary of the conclusions of this paper is as follows ; 1) The object of port administration in Korea has been emphasized on the maximization of efficiency in using the port facilities. Nowadays, however, it should be moved to a direction that port is operated under the compound aims considering the public interests and economy. 2) For a criterian of tariff calculation, A tariff system based on the cost accounting is desirable. In general it is recommended that the cost for construction, management, and operation of port is compensated by the revenue from port operation. Therefore, it is necessary for the administration bodies of each port to establish a tariff system on the basis of the independent profit system. 3) For the investigation of actors of tariff adjustment by the Break-even point analysis, (1) When we conducted the B.E.P analysis using total cost as cost term, we got 3.8% discount in tariff at 12% of target profit rate and 1.5% discount at 15% of rate. when we set the target profit rate as 17% we could have the proper tariff level. (2) When using operating cost as cost term, we got 13.1% discount in tariff at 12% of target profit rate and 10.9% discount at 15% of rate. When setting the target profit rat as 28%, we could have the proper tariff level. 4) Comparing with the tariffs of foreign ports for the basic terminal rate, The tariff level of B.C.T.O.C showed 33% of stevedoring charge and 80% of marshalling charge incurred at Kobe port. The comparison with Singapore port gave 50% of transhipment charge and 17% - 20 % of stevedoring charge. 5) We found that the financial structure of B.C.T.O.C was better than those of other companies and the worth fixed assets ratio was too low. The fact of low worth fixed assets ratio implies that the cargo handling facilities should be increased. Moreover, The return of assets for B.T.T.O.C was good but non-operating expenses were still contained too much in. Therefore, we think that it is necessary for B.C.T.O.C. to rationalize business management. Although the present cargo handing charge for B.C.T.O.C is a proper level in terms of a public corporation, for the final recommendation in connection to the results, It is required to take the rationalization process for business management.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.968-970
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• 1999

The trend of increasing of portable electric devices and demand for global environmental conservation have demands the development of high energy density rechargeable batteries. Lithium polymer battery has excellent theoretical energy density and energy conversion efficiency. Lithium polymer battery, included solid polymer electrolyte(SPE), can be viewed as a system suitable for wide applications from thin film batteries for microelectronics to electric vehicle batteries. The purpose of this paper is to research and development of flyash anode for lithium polymer battery. We investigated AC impedance response and charge/discharge characteristics of flyash/SPE/Li cells. The radius of semicircle associated with the interfacial resistance of flyash/SPE/Li cell increased very slowly during discharge process from 3.11V to 0.478V. And then the cell resistance was decreased at discharge process from 10% SOC to 0% SOC. Also, The radius of semicircle associated with the interfacial resistance of flyash/SPE/Li cell decreasing very slowly during charge process. And then the cell resistance was increased after 20th discharge precess. The discharge capacity based on flyash of 1st and 20th cycles was 276mAh/g and 143mAh/g.

• Design & Manufacturing
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• v.16 no.2
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• pp.20-25
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• 2022

In line with the rapid economic growth of many countries, fossil fuel energy sources are also rapidly depleting. Therefore, the price is also rising rapidly, so it is necessary to develop new and renewable energy sources such as hydropower, geothermal power, nuclear power, wind power and solar energy to replace fossil fuel energy in the future. In this study, development of rotating concentrator module system, development of rotating module control control system, development of lamp and charge control controller, configuration and prototype production of rotating concentrating solar LED street light system, efficiency of rotating concentrating solar LED street light, and power production. The research was conducted in the order of evaluation of comprehensive performance tests such as consumption and consumption. As a result, the developed high-efficiency rotation-concentrating hybrid solar LED street light module system has a 50% higher light-gathering efficiency than existing products by tracing sunlight by self-developing a rotation-collecting module on existing solar LED street lamps according to the characteristics of Korea's topography. and the power generation was improved by more than 40%.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.773-774
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• 2008

As an Embedded system get more complicated, the importance of the software test increases. Especially it is mandatory to test the embeded software for a charge degrade of the development company which is happened due to the error, a danger element clearance to the customer, a performance enhance of the system. In this paper, we propose efficient test method which discovers the bug an embedded system using suitable test case selection and automation test.

• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.80-87
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• 1998

This paper presents a study on the development of discharge model and computer program for assessing the risk of electrostatic discharge(ESD) of charged human body This ESD event is modelled as a two-body problem using spherical conductors, simulating the approach of a charged conductor (human body) to a second conductor (electronic equipment). The charge/discharge process for the model is formulated as a matrix of equations by Maxwell's method. Body potentials, energies and the charge transfer during a discharge are calculated. The developed program, based on the suggested scheme in this paper, is applied to a sample system. The results provide a better understanding of ESD event and demonstrate the usefulness of two-body model in practical applications.