• Composites Research
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• 제34권2호
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• pp.96-100
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• 2021

The lightweight industry continuously demands reliable near-net-shape fabrication where the preform just out-of-machine is close to the final shape. In this study, different half-finished preforms are made π-beams. Then the preforms are unfolded to make a 3D shape with integrated structure of fibers, providing easier handling in the further processing of composites. Several 3D textile preforms are made using weaving technique and are examined after resin infusion for mechanical properties such as inter-laminar shear strength, compressive strength and tensile strength. Considering that the time and labor are important parameters in modern production, 3D weaving technique reduces the manufacturing steps and therefore the costs, such as hand-lay up of textile layers, cutting, and converting into preform shape. Hence this 3D weaving technique offers many possibilities for new applications with efficient composite production.

• Asian Journal of Atmospheric Environment
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• 제8권3호
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• pp.154-161
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• 2014

The present study was undertaken to evaluate the chemical characteristics of Asian dust (hereafter called "AD") particles with the aid of the most advanced micro-PIXE (Particle-induced X-ray emission) analytical technique. To this end, size-selected particles were sampled on a rural peninsula of Korea (Byunsan, 35.37N; 126.27E) during AD and non-AD periods in 2004. The coarse particle (> $2{\mu}m$) number density during an AD event were 170 times higher than those of the non-AD counterpart. The average net-count of silica in individual particles collected on AD event was roughly 11 times higher than that of non-AD counterpart. The X-ray net-counts of trace elements (Zn, Co, Mn, and V) were also considerably high in AD relative to the non-AD day. Particle classification based on the inter ratio analysis of elemental net-count suggests that a large portion of the coarse particles collected during AD event underwent chemical transformation to a certain degree. The visual interpretation of micro-PIXE elemental maps and elemental localization data in and/or on individual AD particles clarified the internal mixture of AD particles with sea-salt and artificial metallic particles.

• Nuclear Engineering and Technology
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• 제41권4호
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• pp.549-560
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• 2009

Over the last three decades, nuclear technology development has played a vital role in the socio-economic development of the Republic of Korea. This study, being the first of its kind, focuses on quantifying the actual economic contribution of nuclear technologies to economic development by evaluating the net benefit of the nuclear power with respect to the country's Gross Domestic Product (GDP). An input-output analysis was employed as a methodological approach to analyze inter-industrial economic activities by calculating the industrial value added as a means of the economic contribution during the period of 1980 to 2005. The industrial value added of nuclear technologies was estimated from the construction and operation of nuclear power (backward-linked industrial value added) and from the industrial activities attributed to the electricity generated by the nuclear power (forward-linked industrial value added). It was found that the total net contribution of nuclear technologies as a percentage share of GDP amounted to 2.38% in 2005.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.680-684
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• 2001

Since establishment some 25 year ago, AMITA Corporation has continued its attempts in meeting customer needs, in reducing costs for waste treatment. The solutions we have proposed in the past made use of our networks entailing Japan as well as the East Asian region. However, as enterprises have changed their perspective approaching environmental issues recently, as needs diversify, AMITA too has been changing its strategy to incorporate the use of Information Technology to provide consulting services. AMITA has set its goals in promoting modernization of the waste treatment industry, and optimizing the recycling market to reduce environmental impacts.

• Nuclear Engineering and Technology
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• 제44권2호
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• pp.207-224
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• 2012

This article discusses selects of some outstanding problems in nuclear reactor analysis, with proposed approaches thereto and numerical test results, as follows: i) multi-group approximation in the transport equation, ii) homogenization based on isolated single-assembly calculation, and iii) critical spectrum in Monte Carlo depletion.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4357-4366
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• 2023

MARS-KS, a domestic regulatory confirmatory code of Republic of Korea, had been developed by integrating RELAP5/MOD2 and COBRA-TF. The integration of COBRA-TF allowed to extend the capability of MARS-KS, limited to one-dimensional analysis, to multi-dimensional analysis. The use of COBRA-TF was mainly focused on subchannel analyses for simulating multi-dimensional behavior within the reactor core. However, this feature has been remained as a legacy without ongoing maintenance. Meanwhile, MARS-KS also includes its own multidimensional component, namely MULTID, which is also feasible to simulate three-dimensional convection and diffusion. The MULTID is capable of modeling the turbulent diffusion using simple mixing length model. The implementation of the turbulent mixing is of importance for analyzing the reactor core where a disturbing cross-sectional structure of rod bundle makes the flow perturbation and corresponding mixing stronger. In addition, the presence of this turbulent behavior allows the secondary transports with net mass exchange between subchannels. However, a series of assessments performed in previous studies revealed that the turbulence model of the MULTID could not simulate the aforementioned effective mixing occurred in the subchannel-scale problems. This is obvious consequence since the physical models of the MULTID neglect the effect of mass transport and thereby, it cannot model the void drift effect and resulting phasic distribution within a bundle. Thus, in this study, the turbulence mixing model of the MULTID has been improved by means of the inter-channel mixing model, widely utilized in subchannel analysis, in order to extend the application of the MULTID to small-scale problems. A series of assessments has been performed against rod bundle experiments, namely GE 3X3 and PSBT, to evaluate the performance of the introduced mixing model. The assessment results revealed that the application of the inter-channel mixing model allowed to enhance the prediction of the MULTID in subchannel scale problems. In addition, it was indicated that the code could not predict appropriate phasic distribution in the rod bundle without the model. Considering that the proper prediction of the phasic distribution is important when considering pin-based and/or assembly-based expressions of the reactor core, the results of this study clearly indicate that the inter-channel mixing model is required for analyzing the rod bundle, appropriately.

• 한국사회복지학
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• 제62권3호
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• pp.31-58
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• 2010

본 연구에서는 서울복지패널자료를 이용하여, 서울시 가구를 대상으로 강남지역과 비강남 지역 간 소득 및 재산격차를 살펴보고, 옥사카 요인분해를 통해 소득 및 재산격차와 관련된 요인을 분석하였다. 분석결과, 강남지역의 월평균 가구소득은 400만원으로, 비강남지역의 가구소득 323만원에 비해, 77만원 정도 높은 것으로 나타났다. 소득격차 중에서, 특성효과가 대부분을 차지하여, 고소득과 관련된 인적자본, 노동시장 특성의 지역간 상이한 분포가 소득격차의 주된 요인으로 작용함을 밝혔다. 한편, 강남지역과 비강남 지역간 순자산격차는 소득격차에 비해 더 심각한 것으로 나타났다. 강남지역 가구의 평균 순자산은 약 4억6천만원으로, 비강남지역의 2억8천만원보다, 약 1억3천만원 정도 높은 것으로 나타났다. 또한 소득격차와는 달리, 계수효과가 순자산 격차의 대부분을 차지하여, 자산의 세대간 이전 등 인적자본 이외의 다른 요인에 의해서 자산격차가 발생할 가능성을 시사하고 있다.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2599-2605
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• 2022

The Korea Retrospective Dosimetry network (KREDOS) performed an inter-laboratory comparison to confirm the harmonization and reliability of the results of retrospective dosimetry using mobile phone. The mobile phones were exposed to ¹⁹²Ir while attached to the human phantoms in the field experiment, and the exposure doses read by each laboratory were compared. This paper describes the reference dosimetry performed to present the reference values for inter-comparison and to obtain additional information about the dose distribution. Reference dosimetry included both measurement using LiF:Mg,Cu,Si and calculation via MCNP simulation to allow a comparison of doses obtained with the two different methodologies. When irradiating the phones, LiF elements were attached to the phones and phantoms and irradiated at the same time. The comparison results for the front of the phantoms were in good agreement, with an average relative difference of about 10%, while an average of about 16% relative difference occurred for the back and side of the phantom. The differences were attributed to the different characteristics of the physical and simulated phantoms, such as anatomical structure and constituent materials. Nevertheless, there was about 4% of under-estimation compared to measurements in the overall linear fitting, indicating the calculations were well matched to the measurements.

• 한국멀티미디어학회논문지
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• 제9권5호
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• pp.635-648
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• 2006

초고속 인터넷의 보급이 대중화되고 콘솔 게임기와 모바일이 네트워크 게임을 지원하면서 온라인 게임 산업이 빠르게 성장하고 있으며, 온라인 게임으로 인한 인터넷 트래픽이 꾸준히 증가하고 있다. 게임 네트워크의 설계나 시뮬레이션을 위해서는 온라인 게임 트래픽의 분석이 선행되어야 하기 때문에, 온라인 게임의 트래픽에 관련된 연구가 국내 외에서 꾸준히 진행되고 있다. 본 논문은 온라인 게임의 트래픽 측정과 분석을 위하여 게임 전용 트래픽 측정 및 분석 툴인 GameNet Analyzer를 제작하여 사용하였다. 서로 다른 장르의 게임인 Quake 3, Starcraft, WoW(World of Warcraft)의 트래픽을 측정하여 플레이어의 수와 게임 플레이 방식에 따른 패킷 크기, 패킷 IAT(inter-arrival time), 데이터 전송률과 패킷 전송률을 분석하고, 측정된 데이터를 이용하여 트래픽을 모델링한다. 이러한 게임 트래픽의 분석이나 트래픽 모델은 효율적인 네트워크 시뮬레이션, 게임 네트워크의 성능 평가, 온라인 게임의 설계 등에 활용될 수 있다.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1428-1435
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• 2019

The total ionizing dose (TID) and non ionizing energy loss (NIEL) effects of 100 MeV phosphorous ($P^{7+}$) and 80 MeV nitrogen ($N^{6+}$) ions on 200 GHz silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were examined in the total dose range from 1 to 100 Mrad(Si). The in-situ I-V characteristics like Gummel characteristics, excess base current (${\Delta}I_B$), net oxide trapped charge ($N_{OX}$), current gain ($h_{FE}$), avalanche multiplication (M-1), neutral base recombination (NBR) and output characteristics ($I_C-V_{CE}$) were analysed before and after irradiation. The significant degradation in device parameters was observed after $100MeV\;P^{7+}$ and $80MeV\;N^{6+}$ ion irradiation. The $100MeV\;P^{7+}$ ions create more damage in the SiGe HBT structure and in turn degrade the electrical characteristics of SiGe HBTs more when compared to $80MeV\;N^{6+}$. The SiGe HBTs irradiated up to 100 Mrad of total dose were annealed from $50^{\circ}C$ to $400^{\circ}C$ in different steps for 30 min duration in order to study the recovery of electrical characteristics. The recovery factors (RFs) are employed to analyse the contribution of room temperature and isochronal annealing in total recovery.