• 한국유체기계학회 논문집
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• 제14권3호
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• pp.23-27
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• 2011

Due to a roots type medium vacuum pump is operated in condition of $1{\sim}10^{-3}$ torr vacuum, it could be applied for production and process of industrial parts, such as precise processing, vaporization, enrichment, separation, casting, metaling, welding, transportation. Therefore, the demand of this pump is increasing nowadays in our industrial markets of semiconductor, electric, electronic, automobile, material, environmental and transporting industries. However, the pumps are almost imported, because the domestic pumps are inferior in fields of vacuum range as under $10^{-1}$torr, relevant techniques(design, fabrication, casting, test, etc.) to the imported ones. In this study, essential parts of the development pump are designed with using of CFD and 3D decodes, FEM for analysing strength and deformation, generated heat, vibration and noise control, and are casted with using of mechanochemistry techniques for decreasing of weights, increasing of heat resistances and abrasion durability of materials for pump caing and impellers especially. Besides, in order to achieve ultimate vacuum around $10^{-3}$torr, this pump is composed of 6 stages, among which 1st stage is operated separately from remained stages. Additionally, a test rig for prototype pumps(300$m^3/h$ and 2,500$m^3/h$) is designed and procured as to apply for multi-staged rootz type vacuum pump, with modification of the test method recommended by KS B 6314 "Positive-displacement oil-sealed rotary vacuum pumps".

• 한국정보통신학회논문지
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• 제17권5호
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• pp.1174-1180
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• 2013

최근에 미래의 디지털 융합을 위한 많은 관심과 요구가 있다. 특히, 정보기술 분야에서 정보기술은 실생활과 밀접한 관련이 있으므로 지역학, 문학, 인문학 등과 같은 다른 학문들과의 융합이 필요하다. 문화지도는 문화와 관련된 다양한 양상들을 점, 선, 기호 등으로 표현하여 지도에 나타낸 것이다. 즉 지도는 디지털 환경에서 문화를 효율적으로 연구할 수 있는 유용한 도구가 된다. 본 논문에서는 지중해지역 연구와 같은 해외지역 연구를 위하여 전자문화지도를 적용할 수 있는 방안을 제시하고 세부적으로 지중해지역 연구를 위한 전자문화지도를 설계 및 구현한다. 본 연구를 통하여 생성된 전자문화지도를 활용하면 해외지역 연구 결과를 시각적으로 표현할 수 있다. 그리고 이를 통하여 연구 결과를 보다 이해하기 쉽게 되고 새로운 연구에 대한 기초 자료로서의 활용이 가능하다. 또한 인문, 지역학과 IT의 융합학으로서, 해외지역을 연구하는 도구 및 연구결과물의 전시 도구로 활용할 수 있다.

• 한국농촌간호학회지
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• 제18권1호
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• pp.27-39
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• 2023

Purpose: This study is a mixed methods research that was conducted to verify factors affecting the working experience of community-based long-term care hospital workers during the COVID-19 pandemic. Methods: The study was carried out from July 19 to November 3, 2021 for 340 nurses who worked at 10 long-term care hospitals located in G city. Results: As the study results, factors that affected job stress of the workers working at community-based long-term care hospitals included job satisfaction (β=-.27, p<.001), work demand (β=-.25, p<.001), fatigue (β=.19, p=.001), and cooperation and leadership (β=-.12, p=.049). It was found that the participants were struggling with physical and mental stress caused by the increased workload due to the preventative measures taken to stop the infection and spread of COVID-19. Despite this, they accepted their situation as necessary to overcome the pandemic and shared the quarantine guidelines of the government and community health centers while actively responding to prevent the spread of COVID-19 under the leadership of their supervisors. However, they were experiencing psychological and emotional burnout in the prolonged pandemic situation. Conclusion: It is considered necessary to help relieve their stress and provide psychological and mental support by adopting a policy to develop and apply comprehensive programs.

• International Journal of Computer Science & Network Security
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• 제24권2호
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• pp.178-188
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• 2024

In the near future, it is expected that there will be billions of connected devices using fifth generation (5G) network services. The recently available base stations (BSs) need to mitigate their loads without changing and at the least monetary cost. The available spectrum resources are limited and need to be exploited in an efficient way to meet the ever-increasing demand for services. Device to Device communication (D2D) technology will likely help satisfy the rapidly increasing capacity and also effectively offload traffic from the BS by distributing the transmission between D2D users from one side and the cellular users and the BS from the other side. In this paper, we propose to apply D2D overlay communication with cognitive radio capability in 5G networks to exploit unused spectrum resources taking into account the dynamic spectrum access. The performance metrics; throughput and delay are formulated and analyzed for CSMA-based medium access control (MAC) protocol that utilizes a common control channel for device users to negotiate the data channel and address the contention between those users. Device users can exploit the cognitive radio to access the data channels concurrently in the common interference area. Estimating the achievable throughput and delay in D2D communication in 5G networks is not exploited in previous studies using cognitive radio with CSMA-based MAC protocol to address the contention. From performance analysis, applying cognitive radio capability in D2D communication and allocating a common control channel for device users effectively improve the total aggregated network throughput by more than 60% compared to the individual D2D throughput without adding harmful interference to cellular network users. This approach can also reduce the delay.

• 한국안전학회지
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• 제27권5호
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• pp.64-69
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• 2012

The concept of SIL is applied in the most of all standards relating to functional system safety. However there are problems for the people to apply SIL to their plants. as these standards don't include sufficient informations. In this regards, this paper will suggest the direction of SIL application and concept based on IEC 61508 and IEC 61511. A Safety Integrity Level(SIL) is the discrete level(one out of possible fours), corresponding to a range of the probability of an E/E/PE (Electric/Electrical/Programmable Electrical) safety-related system satisfactorily performing the specific safety functions under all the stated conditions within a stated period of time. SIL can be divided into the target SIL(or required SIL) and the result SIL. The target SIL is determined by the risk analysis at the analysis phase of safety lifecycle and the result SIL is calculated during SIL verification at the realization phase of safety lifecycle. The target SIL is determined by the risk analysis like LOPA(Layer Of Protection Analysis), Risk Graph, Risk Matrix and the result SIL is calculated by HFT(Hardware Fault Tolerance), SFF(Safe Failure Fraction) and PFDavg(average Probability of dangerous Failure on Demand). SIL is applied to various areas such as process safety, machinery(road vehicles, railway application, rotating equipment, etc), nuclear sector which functional safety is applied. The functional safety is the part of the overall safety relating to the EUC and the EUC control system that depends on the correct functioning of the E/E/PE safety-related systems and other risk reduction measures. SIL is applied only to the functional safety of SIS(Safety Instrumented System) in safety. EUC is the abbreviation of Equipment Under Control and is the equipment, machinery, apparatus or plant used for manufacturing, process, transportation, medical or other activities.

• 농촌지도와개발
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• 제24권4호
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• pp.249-264
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• 2017

Modeling the consumer demand of fresh meat requires its distinct feature which other types of food product does not have. Most of the fresh meat products are likely to be unbranded, bought on a weight basis and affected by macro shocks such as seasonality, holiday effect and the disease incidence. Furthermore, consumers tend to purchase multiple categories of fresh meat in a week. Therefore, we apply a multiple discrete/continuous model on fresh meat consumption data to study the effect of macro shocks on fresh meat sales as well as of price change. As a result shows, Each fresh meat is relatively more likely to be bought in peak season of each fresh meat compared with imported pork which is set as a 'reference category' in this analysis. For clarity of the effect of disease incidence, we perform further analysis regarding the effect of livestock disease on fresh meat purchase probability. It shows that the avian flu in 2014 has strong negative impact on the purchase probability of chicken and the foot-and-mouth disease has negative impact on the purchase probability of pork and beef for part of outbreak periods.

• Journal of the Korean Data and Information Science Society
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• 제11권1호
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• pp.111-126
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• 2000

지방자치제 실시에 따라 우리나라에서도 전국 또는 도 단위의 통계뿐만 아니라 시 군 구 등의 소지역 통계에 대한 수요가 증대되고 있다. 하지만 정부통계 생산을 위해 실시되는 표본조사의 경우 시(특별시, 광역시) 및 도별 통계생산을 목적으로 하기 때문에 신뢰성 있는 소지역 통계를 산출하는 것이 불가능하고, 따라서 이런 소지역 통계생산을 위해 간접 추정 기법을 적극적으로 활용하는 것이 필요하다. 본 논문에서는 정부통계 생산을 위한 소지역 통계 기법의 도입 및 활용 가능성을 검토해 보기 위해 인천광역시 숙박 및 음식점업의 총매출에 대한 구별 소지역 통계를 산출할 수 있는 여러 가지 간접 추정 방법을 제시하고, 아울러 도소매업 총조사 자료를 이용하여 제시된 간접추정량들의 효율성을 비교 분석해 보고자 한다.

• 방송공학회논문지
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• 제25권1호
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• pp.48-57
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• 2020

최근 영상 인식 기술의 급격한 발전으로 도로 교통 CCTV영상 내에서의 객체 분석 요구가 증대되고 있다. 본 논문에서는 도로 교통 CCTV영상 내의 교통량 분석을 위한 계수선(Counting Line)을 도로의 형태에 따라 적응적으로 검출할 수 있는 방법을 제안한다. 우선 도로 위의 차량을 검출하고 검출한 차량의 위치를 이차원 가우시안 형태의 함수로 모델링 한 후, 이를 연속된 프레임 상에서 누적하여 차량의 이동 경로를 표현하는 누적 가우시안 지도를 얻어낸다. 이렇게 얻어낸 누적 가우시안 지도에 군집화 및 선형 회귀를 적용하여 도로의 주방향을 구하고, 이 주방향을 이용하여 최종적으로 교통량 분석을 위한 계수선을 검출한다. 다양한 CCTV상황에서 제안하는 방법을 적용하였을 때 계수선을 효과적으로 검출할 수 있는 것을 실험적으로 확인하였다.

• 상하수도학회지
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• 제29권2호
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• pp.171-182
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• 2015

The economic effects of sewage and wastewater treatment service (SWTS) sector on other sectors have been rarely investigated in the literature. This paper attempts to apply an inter-industry analysis to looking into the economic effects of the SWTS sector. To this end, the most recently published 2012 input-output table is used here. In particular, the SWTS sector is specified as exogeneous to identify the economic effects of the SWTS sector on other sectors. Production-inducing effect, value-added creation effect, and employment-inducing effect are quantified based on demand-driven model. Supply shortage effect and price pervasive effect are also analyzed employing supply-driven model and Leontief price model, respectively. The results show that production-inducing effect and value-added creation effect of a unit of investment or production in SWTS sector are estimated to be 1.7076 and 0.7392, respectively. The employment-inducing effect of one billion of investment or production in the SWTS sector is computed to be 11.0498 persons. The shortage effect of the SWTS sector amounts to 0.8417 won. The overall price effect of the 10% increase in the price of SWTS sector is calculated to be 0.0115%. This quantitative information can be utilized in predicting the economic effects of the SWTS sector-related activities or policy-making.

• STI Policy Review
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• 제5권2호
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• pp.65-95
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• 2014

The recent decades have seen a growing rate of international cooperation in science, technology, and innovation (STI) including in the field of green technologies. However, current approaches to national systems of innovation (NSI) have not kept up with this development. International aspects are rather treated as external conditions within which policymakers operate and respond but not influence. This paper tackles this problem by applying a refined NSI concept that includes an international dimension and complements past frameworks by focusing on those Korean government policies, actors, and activities relevant for the internationalization of STI. Austria and Korea have both formulated differing strategies to acquire international leading positions in the field of innovation and the development of green technologies. In the first step, the paper assesses Korea's international activities within the field of green technologies that transcend national boundaries and establish international connections. The government has still a strong influence on selecting technology areas for strategic funding but our findings show that international STI actors have difficulties in identifying the appropriate point of contact to initiate cooperation or apply for related funding. Second, an external perspective on Korea's international collaborations in the field of green technologies is offered. Austria has tentatively identified the East Asian country as a second-priority cooperation partner for its future STI internationalization activities. Interviews with Austrian stakeholders in the field of green technologies indicate a high interest in cooperation with Korea that is facilitated by a similar business culture based on personal networks. Moreover, researchers and policymakers referred to a shared need of small countries for intelligent decision-making processes regarding potential cooperation partners abroad. However, in order to enhance awareness, visibility and demand for Korean STI cooperation in European countries, more long-term funding programs featuring a more permanent point of contact should be introduced.