• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.630-633
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• 2021

Microphones can convert received voice signals to electric signals. They have been widely used in various industries such as radios, smart devices and vehicles. Recently, the demands for small size and high sensitive microphones are increased according to the minimization of wireless earphone with the development of smart phone. A MEMS system is a good candidate for an ultra-small size microphone of a next generation and a read out IC for high sensitive MEMS sensor is researched from many industries and academies. Since the microphone system has a high sensitivity from environment noise and electric system noise, the system requires a low noise power supply and some low noise design techniques. In this paper, a low noise LDO is presented for small size MEMS microphone systems. The input supply voltage of the LDO is 1.5-3.6V, and the output voltage is 1.3V. Then, it can support to 5mA in the light load condition. The integrated output noise of proposed LDO form 20Hz to 20kHz is about 1.9uV. These post layout simulation results are performed with TSMC 0.18um CMOS technology and the size of layout is 325㎛ × 165㎛.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.1-10
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• 2020

Reactivity controlled compression ignition (RCCI) combustion is one of dual-fuel combustion systems which can be constructed by early diesel injection during the compression stroke to improve premixing between diesel and air. As a result, RCCI combustion promises low nitrogen oxides (NOx) and smoke emissions comparing to those of general dual-fuel combustion. For this combustion system, to meet the intensified emission regulations without emission after-treatment systems, exhaust gas recirculation (EGR) is necessary to reduce combustion temperature with lean premixed mixture condition. However, since EGR is supplied from the front of turbocharger system, intake pressure and the amount of fresh air supplementation are decreased as increasing EGR rate. For this reason, the effect of various EGR rates on the brake power and thermal efficiency of natural gas/diesel RCCI combustion under two different operating conditions in a 6 L compression ignition engine. Varying EGR rate would influence on the combustion characteristic and boosting condition simultaneously. For the 1,200/29 kW and 1,800 rpm/(lower than) 90 kW conditions, NOx and smoke emissions were controlled lower than the emission regulation of 'Tier-4 final' and the maximum in-cylinder pressure was 160 bar for the indurance of engine system. The results showed that under 1,200 rpm/29 kW condition, there were no changes in brake power and thermal efficiency. On the other hand, under 1,800 rpm condition, brake power and thermal efficieny were decreased from 90 to 65 kW and from 37 to 33 % respectively, because of deceasing intake pressure (from 2.3 to 1.8 bar). Therefore, it is better to supply EGR from the rear of compressor, i.e. low pressure EGR (LP-EGR) system, comparing to high pressure EGR (HP-EGR) for the improvement of RCCI power and thermal efficiency.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.817-838
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• 2005

In this paper, the resource adequacy as well as the optimum fuel mix is obtained by the following procedures. First, the regulation body, the government agency, determine the reliability index as well as the optimum portfolio of the fuel mix during the planning horizon. Here, the resources with the characteristics of public goods such as demand-side management, renewable resources are assigned in advance. Also, the optimum portfolio is determined by reflecting the economics, environmental characteristics, public acceptance, regional supply and demand, etc. Second, the government announces the required amount of each fuel-type new resources during the planning horizon and the market participants bid to the government based on their own estimated fixed cost. Here, the government announces the winners of the each auction by plant type and the guaranteed fixed cost is determined by the marginal auction price by plant type. Third, the energy market is run and the surplus of each plant except their cost (guaranteed fixed cost and operating cost) is withdrew by the regulatory body. Here, to induce the generators to reduce their operating cost some incentives for each generator is given based on their performance. The performance is determined by the mechanism of the performance-based regulation (PBR). Here the free-riding performance should be subtracted to guarantee the transparent competition. Although the suggested mechanism looks like very regulated one, it provides two mechanism of the competition. That is, one is in the resource construction auction and the other is in the energy spot market. Also the advantages of the proposed method are it guarantee the proper resource adequacy as well as the desired fuel mix. However, this mechanism should be sustained during the transient period of the deregulation only. Therefore, generation resource planning procedure and market mechanisms are suggested to minimize possible stranded costs.

• Korean Journal of Social Welfare
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• v.61 no.3
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• pp.5-28
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• 2009

The purpose of this study is to examine the legal attribute of subsidiarity principle on the National Basic Livelihood Security Act. The principle of subsidiarity is applied to the regulation for 'fundamental principle of benefits' on the National Basic Livelihood Security Act, therefore it functions as legal theory. However, due to its both positive and negative characteristics it becomes to be interpreted and applied in a different meaning depending on the normative characteristics of related laws. In brief, as the passive meaning of subsidiarity principle guarantees the freedom of civilian by limiting national power, it is reasonable in social control norm like criminal law. However, as nation's active role of intervention and support is required in order to protect basic standard of human life according to the principle of Social(welfare)State, the active meaning of subsidiarity principle is reasonable in Social Security law, especially in public assistance. Hence, the principle of subsidiarity on the National Basic Livelihood Security Act becomes to realize, justice, goal fitness and legal stability when it is operated by system with interpreting in an active meaning.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.32-41
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• 2014

Currently, the three major Korean mobile operators hold a total of 390MHz of bandwidth, but at the current data traffic increase of almost 6 times per year, more frequency bandwidth should be secured in order to meet the exploding data traffic in the future. It is believed that 2.1GHz frequency band is suitable for mobile communication in the light of frequency characteristics and continuity of the band. In this paper, we perform compliance analysis with the international radio regulation for coexistence with the adjacent region in order to use 2.1GHz band for LTE-Advanced. In addition, we verify that 2.1GHz band can coexist with the adjacent band by conducting an interference evaluation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.10
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• pp.71-79
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• 2008

This paper analyzed the voltage induction phenomena on the telecommunication lines by electromagnetic coupling from high-speed A.C. electrified railway. The induced common mode voltages and the induced differential mode voltage on the telecommunication line was measured by notified standard method in the regulation of Korea. The test lines consist of 2 separated lines of 20 m and 300 m in influence distance each for comparison, with 2km inducing length. The analysis is made on the induced voltages from the different influence distances and the different earthing points, and also on the waveform and spectrum distributions. It is proved that the induction is arisen so good and the measured values are fair enough against noise such as the earth voltage differencing, and the current measuring scheme is also rightful.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.1
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• pp.65-72
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• 2018

This study analyzed the condition of marine accident and disaster rate of crew of Korean fishing vessels by vessel type, and checked the Australian safety management system and relevant regulation in Korea to suggest measures to build coastal/offshore fishing vessel safety management system in Korean coastal/offshore fishery. As a result, the power and production amount of Korean coastal/offshore fishing vessel is consistently decreasing while marine accident is increasing. Disaster rate of crew was higher than land industry, especially, the disaster rate of coastal/offshore fishing vessel was very high (100.0‰). Australia applies safety management system differed by vessel type and operation waters which fully considers the characteristics of pertinent vessel. The average accident rate of fishing vessels with gross tonnage over 20 tons among the Korean coastal/offshore fishing vessel was 13.6%, which was significantly higher than fishing vessels with gross tonnage below 20 tons (1.4%). Such result indicates it is urgent to implement safety management system to fishing vessel with gross tonnage over 20 tons and introduce fishing vessel safety supervisor. Establishing safety management system of coastal/offshore fishing vessel will contribute to consistent industrial development by achieving the general goal of reducing marine accident and spreading safety culture.

• Convergence Security Journal
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• v.13 no.5
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• pp.129-135
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• 2013

The revised security industry law revised 17 provisions among 31 provisions in order to root out the violent event. The main contents of the revised security industry law is the intensitfication of the required condition of permission, intensitfication of the obligation, management strengthening of the public resentment of group field, official, reason of expansion of the expenses instructor and guard, dress and equipment, vehicle, intensitfication of the managing director, intensitfication of the punishment, and etc. However, there is the problem including the putting under an obligation of the arrangement new appointment education, cause provider punishment of the service company violence, awareness of the police to the security company, excessive regulation, intensification of punishment problem, supervision power intensitfication of the revised security industry law is excessive the police, and etc. The individual responsibility education completion method and public resentment of group field in addition to is thought in order to solve this that exclusion of the prior education obligation, revision of the security industry law, burden on tax payers of the extra charge, punishment of the violence request contract trader, introduction of the guard qualification certificate system, and etc. are needed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.9
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• pp.116-121
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• 2020

In recent times, fuel economy enhancement and environmental regulation compliance have become the main topics of interest in the automobile industry. Electric vehicles are desirable alternatives to the existing cars that employ internal combustion engines. Specifically, electric vehicles are equipped with inverters, motors, and a gearbox instead of engines and transmission mechanisms. The gearbox is a key component, used to transmit power from the electric motor to the wheel. Therefore, the design of the gearbox is critical. However, most engineers design gears based only on their experience because no standards pertaining to the design factor exist, other than those for the gear ratios. To overcome this problem, the structural stabilities must be examined considering the design factors of the gears. In this study, we considered the module and number of teeth as the main factors. The constraints corresponded to the final gear ratio and fixed distance between each axle of the shafts. Moreover, a structural analysis was conducted, and the variation trend of the maximum equivalent stress against changes in the gear module and number of teeth was examined. By performing such an analysis, the structural stability in the design of a gear system could be effectively investigated.

• Journal of Society of Preventive Korean Medicine
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• v.6 no.1
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• pp.36-50
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• 2002

Health industry, a knowledge based high value-added industry, is being considered as a strategic area for the 21C and many advanced countries are making every endeavors for the promotion of health industry along with information technology, new materials, and mechatronics. Korean health industry, however, has been excluded from the governmental supports as well as bound by strict regulation so far, and there is a significant gap in technology compared with advanced countries. In 21C, technology is the main factor of national competitiveness and that is why the role of R&D institutes are so important in the high level of competition to cope with the technology protection policies of advanced countries. In this article, with Directory of Korean R&D Institutes published by Korea Industry Technology Association, I reviewed the trends of R&D institute of health industry. Main findings of the research can be summarized as follows. The portion of health industry R&D institute is 3.6% of total R&D institute but the amount of R&D investment is over than 5% This means health industry are knowledge based and R&D intensified industry, meanwhile the variations of same industry R&D institutes of health industry is huge in R&D investments and other activities. Regional distributions of health industry institutes show some kind of different patterns in each industry areas. Medical devices and Medical informatics's preference of metropolitan region are distinguished with other industry areas. Many of the institutes are located in same site of it's company rather than operating separate building for R&D specific uses. It is better for transforming ideas to products and close cooperation of research body with product lines, but it is a handicap for networking and communicating with other research institutions too. It takes 18.4yrs for bearing R&D institute on the average. For a long times 'copy products' or 'me too products' policies were easy way to maintain business entities. But recently, it is recognized that research activities are essential component of sustaining it's own business firms. This means technology itself is leading power of corporation itself in the high level of competition.