• 한국농공학회논문집
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• 제64권5호
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• pp.27-39
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• 2022

The smart farm is recognized as a solution for future farmers having positive effects on the sustainability of the poultry industry. Intelligent microclimate control can be a key technology for broiler production which is extremely vulnerable to abnormal indoor air temperatures. Furthermore, better control of indoor microclimate can be achieved by accurate prediction of indoor air temperature. This study developed predictive models for internal air temperature in a mechanically-ventilated broiler house based on the data measured during three rearing periods, which were different in seasonal climate and ventilation operation. Three machine learning models and a mechanistic model based on thermal energy balance were used for the prediction. The results indicated that the all models gave good predictions for 1-minute future air temperature showing the coefficient of determination greater than 0.99 and the root-mean-square-error smaller than 0.306℃. However, for 1-hour future air temperature, only the mechanistic model showed good accuracy with the coefficient of determination of 0.934 and the root-mean-square-error of 0.841℃. Since the mechanistic model was based on the mathematical descriptions of the heat transfer processes that occurred in the broiler house, it showed better prediction performances compared to the black-box machine learning models. Therefore, it was proven to be useful for intelligent microclimate control which would be developed in future studies.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.33-41
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• 2022

Infrastructure procurement has been a major engagement route between China and Africa. This contributes immensely to the gradual infrastructure development seen on the continent. However, maturing discourse purports that these infrastructure collaborations lack intentionality in the continuous development of strategic guidelines and policies for effective implementation despite their uniqueness and criticality. This study proposes that an efficient approach to policy recommendations is through the political and economic analysis (PEA) of these partnerships using public-private partnership (PPP) optics. Unquestionably, these partnerships are representative of the concept of diplomatic transnational public-private partnership (DT-PPP) where infrastructure is procured through the collaboration of public (African governments) and private sector (Chinese state-owned corporations) who provide the managerial, financial, and technical resources for the project implementation. Given the quest for sustainable win-win, this study identifies strategies towards the realization of win-win in the implementation (i.e enablers of win-win) such that fairness and co-benefit, as well as interests, will be achieved. Thus, based on the PEA framework, case scenarios from Ghana and Nigeria using expert interviews identify the criticalities and best practices for the realization of these enablers at the development phase. Findings indicate more effort is required of the public sector (African host countries) in terms of people, structure/institutions, and the implementation processes. Recommendations include improvement of environmental management structures, contract administration procedures, external stakeholders/local community engagement mechanisms, knowledge and technology transfer procedures, and sector-based project operation and maintenance culture and systems. Additionally, actors must have emotional intelligence, good problem-solving abilities, and overall ensure cordial relationships for continued bilateral cooperation.

• 한국ITS학회 논문지
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• 제22권1호
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• pp.25-38
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• 2023

수도권 도시철도는 승객의 통행경로를 추정하지 못하는 경로미확정 이슈가 존재한다. 이 때문에 도시철도 요금은 승객이 최소이동거리를 통행한다는 가정으로 계산된다. 따라서 도시철도의 환승역이 추가되면 최소이동거리가 줄고 요금수입이 줄어드는 구간이 나타난다. 본 연구는 이러한 현상을 요금 Paradox(Shin, 2022)로 규정하고 GTX-A 개통에 의한 요금 Paradox 영향을 추정하였다. 이를 위해 GTX-A의 개통 전후의 시나리오를 구축하여 수도권 통합거리비례요금제에 의한 추가요금의 감소분을 추정하였다. 요금 Paradox는 일일 수입금의 약 0.024%에 해당되는 것으로 분석되었다. 향후 GTX-A, B, C, D 및 경전철 노선 신설 등의 요금정책 의사결정 툴로서 활용될 것으로 기대된다.

• 무역학회지
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• 제42권5호
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• pp.213-232
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• 2017

본 연구는 현재 시행되고 있는 BPO에 대해 제도적 차원에서 주요 쟁점으로 중심으로 신용장 제도와 비교하여 고찰하였다. BPO는 은행간의 약정이기 때문에 지급의무의 이행, 확인, 양도 등에 있어서 신용장제도와 차이를 보이며, 또한 유의해야 할 점이다. BPO은 기본적으로 기능 면에서 신용장과 유사하지만, 별개의 독립적인 제도로 운용되며 정보기술과 데이터를 기반으로 한다. 신용장을 포함한 전통적인 제도 보다는 더 효율적이며 비용 효과적이다. 따라서 전통적인 제도에 대한 전자적 대안으로 보여진다. 본 연구는 선행 연구를 중심으로 이미 발표된 BPO 관련 연구와 자료 등을 통하여 문헌 연구하였다.

• 무역학회지
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• 제43권4호
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• pp.1-25
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• 2018

본 연구는 현재·시행되고 있는 BPO의 디지털 프로세스와 그 지급에 있어서 제도적 관점에서 기존 제도와 비교·분석하였다. BPO는 기능 면에 있어서 신용장과 유사하지만, 전자적 환경을 기반으로 한 은행 간의 지급약정이기 때문에 그 운용에 있어서는 전통적인 제도와는 많은 차이가 있다. 즉 BPO 거래에서의 책임과 의무, 지급 매카니즘, 거래당사자의 역할, 신용장의 확인과 양도 등에 있어서 많은 차이를 보이고 있다. 그러나 BPO는 정보기술을 기반으로 운용되기 때문에 더 효율적이며 비용 효과적이다. 본 연구는 BPO의 선행 연구를 기반으로 이미 발표된 BPO 관련 연구와 자료 등을 중심으로 문헌 연구하였다.

• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.27-34
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• 2023

This paper proposed an Inter-Carrier-Interference (ICI) Canceling Orthogonal Frequency Division Multiplexing (OFDM) receiver for 5G mobile system to support 500 km/h linear motor high speed terrestrial transportation service. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceler is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number 𝒏 to receiver sub-carrier number 𝒍 is generated. In case of 𝒏≠𝒍, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 2 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, for modulation schemes below 16QAM, we confirmed that the difference between BER in a 2 path reverse Doppler shift environment and stationary environment at a moving speed of 500 km/h was very small when the number of taps in the multi-tap equalizer was set to 31 taps or more. We also confirmed that the BER performance in high-speed mobile communications for multi-level modulation schemes above 64QAM is dramatically improved by the use of a multi-tap equalizer.

• International Journal of Computer Science & Network Security
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• 제23권11호
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• pp.128-132
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• 2023

Investment authorities are broad financial institutions that carefully manage investments on behalf of the national government using a long-term value development approach. To provide a stronger structure or framework for In-vestment Authorities to govern the distribution of funds to public and private markets, we've started research to create a blockchain-based prototype for managing and tracking numerous finances of such authorities. We have taken the case study of Oman Investment Authority (OIA) of Sultanate of Oman. Oman's wealth is held in OIA. It is an organization that oversees and utilizes the additional capital generated by oil and gas profits in public and private markets. Unlike other Omani funds, this one focus primarily on assets outside the Sultanate. The operation of the OIA entails a huge number of transactions, necessitating a high level of transparency and administration among the parties involved. Currently, OIA relies on various manuals to achieve its goals, such as the Authorities and Responsibilities manual, the In-vestment Manual, and the Code of Business Conduct, among others. In this paper, we propose a Blockchain based framework to manage the operations of OIA. Blockchain is a part of the Fourth Industrial Revolution, and it is re-shaping every industry. The main components of every blockchain are assets and participants. The funds are the major assets in the proposed study, and the participants are the various fund shareholders/recipients. The block-chain's transactions are all safe, secure, and immutable, and it's part of a trustless network. The transactions are simple to follow and verify. By replacing intermediary firms with smart contracts, blockchain-based solutions eliminate any middlemen in the fund allocation process.

• 대한토목학회논문집
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• 제43권6호
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• pp.763-774
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• 2023

도시 하류의 가용수량과 관련된 생활용수 회귀수량은 아직까지 정확한 회귀수량 파악이 어려운 상황이다. 본 연구에서는 생활용수 물순환시스템을 면(面)적 개념으로 물 유입, 물 전달, 물 유출 단계로 정의하였다. 대상지는 전라남도 함평군 일대로 선정했으며 물순환계통도 작성 및 완전·불완전 계측지점의 분류를 통해 단일 유입~단일 유출지점으로 설정하였다. 총 6년(2017년 1월 1일~2022년 12월 31일)간 일단위의 유입량·유출량 자료로 시계열예측모형(ARIMA 모형, 전이함수모형)을 구축하였고 학습기간과 검증기간으로 분리하여 유입량·유출량을 예측하였다. 그 결과, 두 모형 모두 안정적인 잔차와 통계적 유의성 확보로 단기 예측 실현 가능성을 보여 초기 단계의 물순환시스템을 구현하였다. 향후에는 불완전 계측지점, 미계측지점, 기상조건을 추가하고 최적의 모형을 선정하여 대상 유역의 실제 회귀량을 예측하고 효율적인 물 운영이 가능하길 기대해본다.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1066-1080
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• 2024

SMART100 has a containment pressure and radioactivity suppression system (CPRSS) for passive containment cooling system (PCCS). This prevents overheating and over-pressurization of a containment through direct contact condensation in an in-containment refueling water storage tank (IRWST) and wall condensation in a CPRSS heat exchanger (CHX) in an emergency cool-down tank (ECT). The Korea Atomic Energy Research Institute (KAERI) constructed scaled-down test facilities, SISTA1 and SISTA2, for the thermal-hydraulic validation of the SMART100 CPRSS. Three separate effect tests were performed using SISTA1 to confirm the heat removal characteristics of SMART100 CPRSS. When the low mass flux steam with or without non-condensable gas is released into an IRWST, the conditions for mitigation of the chugging phenomenon were identified, and the physical variables were quantified by the 3D reconstruction method. The local behavior of the non-condensable gas was measured after condensation inside heat exchanger using a traverse system. Stratification of non-condensable gas occurred in large tank of the natural circulation loop. SISTA2 was used to simulate a small break loss-of-coolant accident (SBLCOA) transient. Since the test apparatus was a metal tank, compensations of initial heat transfer to the material and effect of heat loss during long-term operation were important for simulating cooling performance of SMART100 CPRSS. The pressure of SMART100 CPRSS was maintained below the design limit for 3 days even under sufficiently conservative conditions of an SBLOCA transient.

• Journal of Trauma and Injury
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• 제37권1호
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• pp.74-78
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• 2024

Inferior vena cava (IVC) injuries can have fatal outcomes and are associated with high mortality rates. Patients with IVC injuries require multiple procedures, including prehospital care, surgical techniques, and postoperative care. We present the case of a 67-year-old woman who stabbed herself in the abdomen with a knife, resulting in an infrarenal IVC injury. We shortened the transfer time by transporting the patient using a helicopter and decided to perform direct-to-operating room resuscitation by a trauma physician in the helicopter. The patient underwent laparotomy with IVC ligation for damage control during the first operation. The second- and third-look operations, including previous suture removal, IVC reconstruction, and IVC thrombectomy, were performed by a trauma surgeon specializing in cardiovascular diseases. The patient was discharged without major complications on the 19th postoperative day with rivaroxaban as an anticoagulant medication. Computed tomography angiography at the outpatient clinic showed that thrombi in the IVC and both iliac veins had been completely removed. Patients with IVC injuries can be effectively treated using a trauma system that includes fast transportation by helicopter, damage control for rapid hemostasis, and expert treatment of IVC injuries.