• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.324-324
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• 2017

기후변화로 인하여 강우특성이 변화하여 기존 치수시설물의 설계능력을 초과하는 홍수사상이 빈발하고 있다. 특히, 도심지내의 하천변 저지대는 대표적인 침수취약지역으로 강우사상이 설계빈도를 상회하는 경우 침수피해를 입을 수 있는 지역이다. 기후변화로 인하여 강우특성이 변화하는 상황에서 기존 빗물펌프장의 치수능력 증대 또는 신규시설의 설치가 필요하지만, 부지확보의 어려움으로 신규사업의 진행이 어려움을 겪고 있는 상황이다. 이와 같은 문제점에 대비하여 기존 빗물펌프장 설계단계에서 고려하지 않고 있는 요소의 추가적인 검토가 필요하다. 빗물펌프장의 유수지 용량 설계단계에서는 유입되는 우수의 수문곡선과 펌프의 최대토출량을 비교하여 잔류하게되는 우량수문곡선을 적분하여 설계용량을 산정한다. 그러나, 빗물펌프장의 실제 운영단계에서는 유수지 내의 수위와 하천의 수위를 고려하여 단계적으로 펌프를 가동하기 때문에 설계단계의 가정과 차이가 발생하게 된다. 또한, 빗물펌프장은 넓은 부지에 유입구와 흡수정을 설치함에 있어서 배치에 따른 유수지내의 흐름특성을 고려하지 않고 있다. 흡수정 설계단계에서는 흡수정으로 유입되는 흐름 특성이 토출성능에도 영향을 미칠 수 있으므로 이에 대한 분석이 필요한 상황이다. 본 연구에서는 빗물펌프장의 유수지 및 흡수정 형상과 펌프운영 기준을 반영하여 2차원 수치해석을 수행하고 유수지내의 흐름특성을 재현하였다. 수치모의결과, 유수지 형상에 따라서 흐름특성이 상이하고 흡수정 인근의 흐름특성이 유수지와 흡수정 배치에 영향을 받음을 확인할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.8-8
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• 2021

2020년 6월 발전용댐의 다목적활용 선포로 국내 발전용댐은 발전에 제한되었던 기능이 홍수조절, 용수공급, 환경개선 등으로 확장되었다. 특히 북한강 수계에는 화천댐부터 팔당댐까지 5개의 발전용댐이 직렬로 배치되어 있기 때문에 기능에 따른 통합연계운영은 해당 수계 내 수자원 활용의 효율성을 높여줄 것으로 기대되고 있다. 그러나, 발전용댐의 주요 목적인 발전과 부가 목적인 홍수조절 및 용수공급은 수자원 활용 측면에서 상반된 운영을 수행해야 하므로 효율성 측면에서 세심한 운영이 필요하다. 국내에는 과거 발전용댐의 운영과 관련한 많은 연구가 진행되어 왔고 최근에는 회복탄력성 개념을 도입하여 단일 발전용댐에 대한 운영방안을 제시하였다(Kim et al., 2020). 그러나 발전가능수위의 회복력으로 정의된 발전용댐의 회복탄력성은 직렬 배치되어 있을 경우 상·하류 상황에 따라 달라질 수 있다. 즉, 상·하류의 방류상황에 따라 단일 댐 혹은 수계 내 존재하는 발전용댐의 발전기능, 이수기능, 치수기능은 상호간섭 영향을 받게 된다. 따라서, 본 연구에서는 회복탄력성 개념을 직렬배치된 발전용댐에 적용하여 댐 연계운영방안을 제시하고자 한다. 과거 유입량 자료를 활용하여 발전용댐 연계 모의운영을 수행하였고, 그 결과로 수계 내 발전용댐 전체의 회복탄력성, 발전량, 홍수위험일수, 무효방류량 등을 평가하였다. 또한 단일 댐 운영과 비교하여 연계운영 효과에 대해 분석하였다. 향후 병렬배치의 댐 운영과 경제성 평가분석이 이뤄진다면 국내 한강수계 실정에 맞는 발전용댐 최적 운영기준을 제시할 수 있을 것으로 기대된다.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.18 no.2
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• pp.87-100
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• 2022

Unit capacity factor (utilization rate) of nuclear power plants (NPPs) is an important performance indicator. Since the first commercial operation of Kori Unit 1 began in April 1978, the utilization rate of domestic NPPs has gradually increased, reaching 90% from the end of the 1990s. However, due to various issues such as the Fukushima accident in 2011, corrosion of the CLP, the utilization rate dropped to 65~80%. In the early 1980s, the utilization rate of the U.S. NPPs was around 60%. However, since 2004, it has been consistently maintained above 90%. Therefore, in this study, we first examined the causes of declining the utilization rate in domestic NPPs. Next, the significances of the utilization rates are reviewed in five aspects: investment capability, electricity rate, safety and export, etc., with discussion on the current status of the utilization rates in the U.S. Based on this, three key factors are derived as the reasons of the increasing: equipment reliability program, on-line maintenance and the pursuit of institutional rationality. And finally, by synthesizing above results, the measures for increasing the utilization rate of domestic NPPs are proposed in terms of equipment management, institutional improvements, and personnel resources.

• The Journal of the Acoustical Society of Korea
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• v.29 no.6
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• pp.402-409
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• 2010

In this paper, we propose an efficient integrated suppression algorithm based on combined power of acoustic echo and background noise. The proposed method combines the acoustic echo and noise power by the weighting parameter derived from the decision rule based on the estimated echo to noise power ratio. Therefore, in the proposed approach, the acoustic echo and noise signal are able to be reduced through only one suppression filter based on the estimated combined power. The proposed unified structure improves the problems of the residual echo and noise resulted from the conventional unified structure where the noise suppression (NS) operation is placed after the acoustic echo suppression (AES) algorithm or vice versa. The performance of the proposed algorithm is evaluated by the objective test under various environments and yields better results compared with the conventional scheme.

• The Korean Journal of Air & Space Law and Policy
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• v.2
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• pp.31-67
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• 1990

One of the first issues which arose in the evolution of air law was the determination of the vertical limits of airspace over private property. In 1959 the UN in its Ad Hoc Committee on the Peaceful Uses of Outer Space, started to give attention to the question of the meaning of the term "outer space". Discussions in the United Nations regarding the delimitation issue were often divided between those in favour of a functional approach ("functionalists"), and those seeking the delineation of a boundary ("spatialists"). The functionalists, backed initially by both major space powers, which viewed any boundary as possibly restricting their access to space(Whether for peaceful or military purposes), won the first rounds, starting with the 1959 Report of the Ad Hoc Committee on the Peaceful Uses of Outer Space which did not consider that the topic called for priority consideration. In 1966, however, the spatialists, were able to place the issue on the agenda of the Outer Sapce Committee pursuant to Resolution 2222 (xxx1). However, the spatialists were not able to present a common position since there existed a variety of propositions for delineation of a boundary. Over the years, the funtionalists have seemed to be losing ground. As the element of location is a decisive factor for the choice of the legal regime to be applied, a purely functional approach to the regulation of activities in the space above the Earth does not offer a solution. It is therefore to be welcomed that there is clear evidence of a growing recognition of the defect inherent to such an approach and that a spatial approach to the problem is gaining support both by a growing number of States as well as by publicists. The search for a solution of the problem of demarcating the two different legal regimes governing the space above the Earth has undoubtedly been facilitated, and a number of countries, among them Argentina, Belgium, France, Italy and Mexico have already advocated the acceptance of the lower boundary of outer space at a height of 100km. The adoption of the principle of sovereignty at that height does not mean that States would not be allowed to take protective measures against space activities above that height which constitute a threat to their security. A parallel can be drawn with the defence of the State's security on the high seas. Measures taken by States in their own protection on the high seas outside the territorial waters-provided that they are proportionate to the danger-are not considered to infringe the principle of international law. The most important issue in this context relates to the problem of a right of passage for space craft through foreign air space in order to reach outer space. In the reports to former ILA Conferences an explanation was given of the reasons why no customary rule of freedom of passage for aircraft through foreign territorial air space could as yet be said to exist. It was suggested, however, that though the essential elements for the creation of a rule of customary international law allowing such passage were still lacking, developments apperaed to point to a steady growth of a feeling of necessity for such a rule. A definite treaty solution of the demarcation problem would require further study which should be carried out by the UN Outer Space Committee in close co-operation with other interested international organizations, including ICAO. If a limit between air space and outer space were established, air space would automatically come under the regime of the Chicago Convention alone. The use of the word "recognize" in Art. I of chicago convention is an acknowledgement of sovereignty over airspace existing as a general principle of law, the binding force of which exists independently of the Convention. Further it is important to note that the Aricle recognizes this sovereignty, as existing for every state, holding it immaterial whether the state is or is not a contracting state. The functional criteria having been created by reference to either the nature of activity or the nature of the space object, the next hurdle would be to provide methods of verification. With regard to the question of international verification the establishment of an International Satelite Monitoring Agency is required. The path towards the successful delimitation of outer space from territorial space is doubtless narrow and stony but the establishment of a precise legal framework, consonant with the basic principles of international law, for the future activities of states in outer space will, it is still believed, remove a source of potentially dangerous conflicts between states, and furthermore afford some safeguard of the rights and interests of non-space powers which otherwise are likely to be eroded by incipient customs based on at present almost complete freedom of action of the space powers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.262-269
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• 2016

This study examined the influent of a sulfur denitrification reactor using nitrified effluent from a batch type reactor. The denitrification efficiency was compared according to the injection type. The nitrogen removal effects were compared with the changes in the EBCT and nitrogen concentration of the influent to determine the optimal operation conditions with the selected injection type. A denitrification efficiency evaluation of a reactor according to the change in injection type and up-flow was performed using a lower organic concentration of the effluent than the down-flow because of the re-precipitation of desorbed microbes and spilled solids. In the up-flow type, organics were controlled by the low concentration than the down-flow type because of solid re-precipitation. The T-N removal efficiency of the up-flow type was 73.3~90.2%, which was more that 10% higher that down-flow type. This means that the up-flow type has a great advantage in removing T-N and organics. The T-N removal efficiency by EBCT at 1hr was 47.3%, and was 88.1% and 90.5% by EBCT 3hr and 5hr, respectively. Therefore, the optimal operation conditions to remove nitrogen was considered to be EBCT for 3hr. After careful consideration of rule of law and T-N removal effects, the T-N load factor in the reactor should remain below $0.443kgT-N/m^3{\cdot}day$ to maintain the legal total nitrogen concentration for discharge, which is 20mg/L.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.120-125
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• 2004

There are very few numbers of 115K FPP (Fixed Pitch Propulsion) Tankers for the Baltic ice class IA because the minimum power requirement of FMA (Finish- Swedish Maritime Association) needs quite large engine power and the 40 m Beam is out of calculation range of FMA minimum power requirements. The shipyard has no choice except to increase the engine power to satisfy FMA minimum power requirement Rule. And the operation cost, efficiency of hullform and its building cost are not good from the ship owners' point of view To solve this problem, the experience of ice breaking tanker development and the ice tank test results were adopted. The main idea to reduce the ice resistance is by reducing waterline angle at design load waterline. The reason behind the main idea is to reduce the ice-clearing force. Two hull forms were developed to satisfy Baltic Ice class IA. Two ice tank tests and one towing tank test was performed at MARC (Kvaener-Masa Arctic Research Center) and SSMB (Samsung Ship Model Basin) facilities, respectively. The purpose of these tests was to verify the performance in ice and open water respectively The hull form 2 shows less speed loss compared to Hull form 1 in open water operation but hull form 2 shows very good ice clearing ability. finally the Hull Form 2 satisfying Baltic ice class IA. The merit of this hull form is to use the same engine capacity and no major design changes in hull form and other related designs But the hull structure has to be changed according to the ice class grade. The difference in two hull form development methods, ice model test methods and analysis methods of ice model test will be described in this paper.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.1-9
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• 2009

A full adders is an important component in applications of digital signal processors and microprocessors. Thus it is imperative to improve the power dissipation and operating speed for designing a full adder. We propose a new adder with modified version of conventional static CMOS and pass transistor logic. The carry-out generation circuit of the proposed full adder is different from the conventional XOR-XNOR structure. The output Cout of module III is generated from input A, B and Cin directly without passing through module I as in conventional structure. Thus output Cout is faster by reducing operation step. The proposed module III uses the static CMOS logic style, which results full-swing operation and good driving capability. The proposed 1bit full adder has the advantages over the conventional static CMOS, CPL, TGA, TFA, HPSC, 14T, and TSAC logic. The delay time is improved by 4.3% comparing to the best value known. PDP(power delay product) is improved by 9.8% comparing to the best value. Simulation has been carried out using a $0.18{\mu}m$ CMOS design rule for simulation purposes. The physical design has been verified using HSPICE.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2551-2561
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• 2014

Several algorithms have been developed to detect AFIB(Atrial Fibrillation) which either rely on the linear and frequency analysis. But they are more complex than time time domain algorithm and difficult to get the consistent rule of irregular RR interval rhythm. In this study, we propose algorithm for optimal value detection of irregular RR interval for AFIB classification based on linear analysis. For this purpose, we detected R wave, RR interval, from noise-free ECG signal through the preprocessing process and subtractive operation method. Also, we set scope for segment length and detected optimal value and then classified AFIB in realtime through liniar analysis such as absolute deviation and absolute difference. The performance of proposed algorithm for AFIB classification is evaluated by using MIT-BIH arrhythmia and AFIB database. The optimal value indicate ${\alpha}=0.75$, ${\beta}=1.4$, ${\gamma}=300ms$ in AFIB classification.

• Journal of Intelligence and Information Systems
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• v.25 no.4
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• pp.123-139
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• 2019

The job classification system of major job sites differs from site to site and is different from the job classification system of the 'SQF(Sectoral Qualifications Framework)' proposed by the SW field. Therefore, a new job classification system is needed for SW companies, SW job seekers, and job sites to understand. The purpose of this study is to establish a standard job classification system that reflects market demand by analyzing SQF based on job offer information of major job sites and the NCS(National Competency Standards). For this purpose, the association analysis between occupations of major job sites is conducted and the association rule between SQF and occupation is conducted to derive the association rule between occupations. Using this association rule, we proposed an intelligent job classification system based on data mapping the job classification system of major job sites and SQF and job classification system. First, major job sites are selected to obtain information on the job classification system of the SW market. Then We identify ways to collect job information from each site and collect data through open API. Focusing on the relationship between the data, filtering only the job information posted on each job site at the same time, other job information is deleted. Next, we will map the job classification system between job sites using the association rules derived from the association analysis. We will complete the mapping between these market segments, discuss with the experts, further map the SQF, and finally propose a new job classification system. As a result, more than 30,000 job listings were collected in XML format using open API in 'WORKNET,' 'JOBKOREA,' and 'saramin', which are the main job sites in Korea. After filtering out about 900 job postings simultaneously posted on multiple job sites, 800 association rules were derived by applying the Apriori algorithm, which is a frequent pattern mining. Based on 800 related rules, the job classification system of WORKNET, JOBKOREA, and saramin and the SQF job classification system were mapped and classified into 1st and 4th stages. In the new job taxonomy, the first primary class, IT consulting, computer system, network, and security related job system, consisted of three secondary classifications, five tertiary classifications, and five fourth classifications. The second primary classification, the database and the job system related to system operation, consisted of three secondary classifications, three tertiary classifications, and four fourth classifications. The third primary category, Web Planning, Web Programming, Web Design, and Game, was composed of four secondary classifications, nine tertiary classifications, and two fourth classifications. The last primary classification, job systems related to ICT management, computer and communication engineering technology, consisted of three secondary classifications and six tertiary classifications. In particular, the new job classification system has a relatively flexible stage of classification, unlike other existing classification systems. WORKNET divides jobs into third categories, JOBKOREA divides jobs into second categories, and the subdivided jobs into keywords. saramin divided the job into the second classification, and the subdivided the job into keyword form. The newly proposed standard job classification system accepts some keyword-based jobs, and treats some product names as jobs. In the classification system, not only are jobs suspended in the second classification, but there are also jobs that are subdivided into the fourth classification. This reflected the idea that not all jobs could be broken down into the same steps. We also proposed a combination of rules and experts' opinions from market data collected and conducted associative analysis. Therefore, the newly proposed job classification system can be regarded as a data-based intelligent job classification system that reflects the market demand, unlike the existing job classification system. This study is meaningful in that it suggests a new job classification system that reflects market demand by attempting mapping between occupations based on data through the association analysis between occupations rather than intuition of some experts. However, this study has a limitation in that it cannot fully reflect the market demand that changes over time because the data collection point is temporary. As market demands change over time, including seasonal factors and major corporate public recruitment timings, continuous data monitoring and repeated experiments are needed to achieve more accurate matching. The results of this study can be used to suggest the direction of improvement of SQF in the SW industry in the future, and it is expected to be transferred to other industries with the experience of success in the SW industry.