• 한국통신학회논문지
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• 제34권10C호
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• pp.937-945
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• 2009

본 논문에서는 변수노드의 차수가 3인 정칙 LDPC 부호의 absorbing 집합(AS)에 대한 여러 가지 성질을 알아본다. Girth가 인 경우, 가장 작은 absorbing 집합은 AS임을 보였고, 인 경우 이 AS가 가장 작은 fully absorbing 집합임을 증명하였다. 또한 (3,5) Tanner LDPC 부호에서 오류 마루의 주원인으로 꼽히는 몇몇 absorbing 집합의 critical number를 유도하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제4권1호
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• pp.22-27
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• 2015

Transform-domain JND (Just Noticeable Difference)-based for PVC (Perceptual Video Coding) is often performed in quantization processes to effectively remove perceptual redundancy. This study examined the JND-suppression effects on quantized coefficients of transform in HEVC (High Efficiency Video Coding). To reveal the JND-suppression effect in quantization, the properties of the floor functions were used for modeling the quantized coefficients, and a JND-adjustment process in an HEVC-compliant PVC scheme was used to tune the JND values by analyzing the JND suppression effect. In the experimental results, the bitrate reduction decreases slightly, but the PSNR and perceptual quality are improved significantly when the proposed JND adjustment process is applied.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.224-225
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• 2018

Modern people are more interested in the indoor environment as they spend more time indoors than in the past. Among the air pollutants in the indoor air, ladon gas is a colorless, tasteless, odorless, inert gas produced by nuclear decomposition of naturally occurring uranium in rocks and soils. It has been proven that ladon gas is introduced into the room through cracks on the floor of the building or basement wall, and it causes various diseases such as lung cancer when exposed to radon during human breathing. The US Environmental Protection Agency (EPA) specifies 4pCi / L as a necessary measure for radon, and the Korea Environmental Protection Agency has implemented comprehensive indoor radon management measures since 2007. Therefore, in this study, we intend to adsorb and reduce radon in indoor air pollutants.

• 방송공학회논문지
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• 제5권2호
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• pp.273-280
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• 2000

건물 외부에 위치하는 송신기와 건물 내부에 위치하는 수신기 사이의 채널 특성을 분석하기 위해 전파 추적 기법을 기반으로 한 모의 실험을 수행하였다. 본 모의 실험에서는 건물 내에 29개의 수신기를 설치하고, 각 수신기에서의 수신 특성을 다중 경로를 통해 수신된 여러 개의 신호의 상호 간섭 패턴을 이용하여 분석하였다. 모의 실험 결과에서 수신기의 위치와 송신기의 위치 및 전파의 편파 특성에 따라 수신 특성이 다르게 나타났고, 상쇄 간섭으로 인해 창가 쪽에 위치한 수신기의 수신 파워가 건물 안 쪽에 위치한 수신기의 수신 파워보다 작게 나타나는 경우도 있었다. 본 논문에서는 채널 파라미터들, 즉 mean excess delay와 rms delay spread를 통해 송신기와 수신기간의 채널 특성 분석도 수행하였다.

• 콘크리트학회지
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• 제10권1호
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• pp.171-178
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• 1998

본 연구는 폴리우레탄 콘크리트 패널의 바닥재로서의 이용 가능성을 검토하기 위하여 수행되었다. 따라서 각종 요구되는 성능에 부합되는 배합을 달리한 폴리우레탄 콘크리트를 제작하여 각종 물성 실험을 실시하였다. 또한 폴리우레탄 콘크리트 패널을 제작하여 직접 현장에서의 시공한 수 바닥충격음 실험을 실시, 그 효과를 평가하였다. 실험결과, 폴리우레탄 콘크리트의 성능과 코스트의 밸런스가 적절하게 확보된 최적배합비를 도출할 수 있었으며, 특히 기존 바닥구조에 비해 공동주택의 층간소음을 어느 정도 줄일 수 있고 동시에 시공공정의 단축과 단열효과로 보다 더 우수한 바닥난방구조를 제안할 수 있다.

• Structural Engineering and Mechanics
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• 제15권4호
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• pp.381-394
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• 2003

While constructing multistorey buildings with reinforced concrete framed structures it is a common practice to provide parking space for vehicles at the ground floor level. This floor will generally consist of open frames without any infilled walls and is called an open-storey. From a post disaster damage survey carried out, it was noticed that during the January 26, 2001 Bhuj (Gujarat, India) earthquake, a large number of reinforced concrete framed buildings with open-storey at ground floor level, suffered extensive damage and in some cases catastrophic collapse. This has brought into sharp focus the need to carry out systematic studies on the seismic vulnerability of such buildings. Determination of vulnerability requires realistic structural response estimations taking into account the stochasticity in the loading and the system parameters. The stochastic finite element method can be effectively used to model the random fields while carrying out such studies. This paper presents the details of stochastic finite element analysis of a five-storey three-bay reinforced concrete framed structure with open-storey subjected to standard seismic excitation. In the present study, only the stochasticity in the system parameters is considered. The stochastic finite element method used for carrying out the analysis is based on perturbation technique. Each random field representing the stochastic geometry/material property is discretised into correlated random variables using spatial averaging technique. The uncertainties in geometry and material properties are modelled using the first two moments of the corresponding parameters. In evaluating the stochastic response, the cross-sectional area and Young' modulus are considered as independent random fields. To study the influence of correlation length of random fields, different correlation lengths are considered for random field discretisation. The spatial expectations and covariances for displacement response at any time instant are obtained as the output. The effect of open-storey is modelled by suitably considering the stiffness of infilled walls in the upper storey using cross bracing. In order to account for changes in soil conditions during strong motion earthquakes, both fixed and hinged supports are considered. The results of the stochastic finite element based seismic analysis of reinforced concrete framed structures reported in this paper demonstrate the importance of considering the effect of open-storey with appropriate support conditions to estimate the realistic response of buildings subjected to earthquakes.

• 한국산림과학회지
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• 제98권5호
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• pp.609-617
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• 2009

This study was conducted to investigate ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica Ledeb.) stand of Mongolia. The species abundance and biodiversity indices were higher in burned and clear-cut stands than those of reference stand, but boreal understory species, such as Vaccinium vitis-idaea, Pyrola incarnata, Linnea borealis and Maianthemum bifolium, completely disappeared and was replaced by sedge species, such as Carex duriuscula, C. lanceolata, C. pediformis, Poa attenuata and P. pratensis. During the research period, temperature increased by an average of $1.6^{\circ}C$ in burned stand and $1.7^{\circ}C$ in clear-cut stand compared to reference stand, but RH sharply decreased up to 15.7% in clear-cut stand. This result indicates that Larix sibirica stand became warmer and drier after forest fire and clear-cutting, and contributed to the abundance of sedge and grass species in the understory. Moreover, intense occupation of tall sedge grass after forest fire and clear-cutting had a vital role as obstacle on natural regeneration of Larix sibirica. The similarity of species composition between reference and burned stands was higher (73.6%) than between reference and clear-cut stands (63.8%). Soil moisture significantly decreased after forest fire and clear-cutting, and the extent of decrease was more severe in the clear-cut stand. The chemical properties at soil organic layer were significantly affected by forest fire and clear-cutting but not the mineral horizons. Inorganic nitrogen of the forest floor significantly decreased in the clear-cut stand ($1.1{\pm}0.4mg{\cdot}kg^{-1}$) than that of the burned ($4.5{\pm}2.3mg{\cdot}kg^{-1}$) and reference stands ($5.0{\pm}2.3mg{\cdot}kg^{-1}$). Available P of the forest floor significantly increased after fire, whereas it decreased after clear-cutting. These results indicate that existence of boreal understory vegetation, and changes in soil moisture and available P are distinct attributes applicable as ecological indicators for identifying forest degradation in Mongolia.

• 대한간호학회지
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• 제45권6호
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• pp.783-801
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• 2015

Purpose: The purpose of this study is to provide a comprehensive overview of the various measures available for assessment of oxaliplatin-induced peripheral neuropathy (OXLIPN) and to evaluate the measurement properties of each assessment tool. Methods: A systematic review was conducted to identify existing measures for OXLIPN found in the databases of PubMed, Cochrane Library, Embase, RISS and KoreaMed. The quality of the 24 identified tools was evaluated based on their properties of measurement including content validity, internal consistency, criterion validity, construct validity, reproducibility, responsiveness, floor-ceiling effects and interpretability. Results: Ten (41.7%) of the 24 tools were identified as specific measures for assessing OXLIPN and the most popular type of measures were clinical grading systems by clinicians (58.3%) and only 29.2% of measures were identified as patient reported outcomes. The most frequently used tool was National Cancer Institute-Common Toxicity Criteria (NCI-CTC), but the validity of NCI-CTC has not been reported appropriately. Overall, the Neuropathic Pain Symptom Inventory (NPSI) received the best psychometric scores, and the Chemotherapy-induced Peripheral Neuropathy Assessment Tool (CIPNAT) and Functional Assessment of Cancer Therapy/Gynaecologic Oncology Group-neurotoxicity-12 (FACT/GOG-Ntx-12) followed NPSI. Conclusion: To select appropriate measure, evidences should be accumulated through the clinical use of tools. Therefore, practitioner and researchers are urged to report relevant statistics required for the validation of the currently used measures for assessment of OXLIPN.

• Journal of Forest and Environmental Science
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• 제29권1호
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• pp.29-37
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• 2013

The study was carried out in two different forest types viz., Banj oak and Chir pine forests to assess the variation in forest species composition and soil properties along altitudinal gradients in the Garhwal Himalayas. The results of the study showed that between the forests soil moisture was higher in Banj oak forest because of closed canopy and dense forest compared to Chir pine forest. The sand particles were reported higher in Banj oak forest which might be due to the addition of organic matter favouring coarse structure of soil, helping in holding maximum water in soils. However in the Chir pine forest low amount of soil organic matter and presence of clayey soil, develops soil compactness which reduces the penetration of water resulting in high soil bulk density. The higher accumulation of litter and presence of moisture in Banj oak forest favours higher nutrient level of nitrogen, phosphorus and potassium compared to Chir pine forest. The soil organic carbon also reduced with increasing altitude at both gradients. While bulk density has reverse trend with soil organic carbon in both the forests at different peaks of same region. In Banj oak forest, the highest density and total basal cover was reported 1,100 tree $ha^{-1}$ and 58.86 $m^2\;ha^{-1}$ respectively. However, the highest values of density and total basal cover of Chir pine forest was 560 tree$ha^{-1}$ and 56.94 $m^2\;ha^{-1}$ respectively. The total density and basal cover of both the forests reduced with increasing altitude. The study concludes that Banj oak forest has better nutrient cycling ability, well developed foest floor and has a greater protective and productive features compared to the Chir pine forest which is without lower vegetation cover and having only pine litter accumulation which does not allow any other species to grow.

• 한국재난정보학회 논문집
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• 제20권2호
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• pp.293-301
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• 2024

연구목적: 환경부 통계에 의하면 2014년부터 2023년까지 국내 화재·폭발사고가 132건 이상에 이르는 것을 알 수 있다. 이중 화재·폭발사고는 발생 시 규모나 영향이 상대적으로 매우 커서 주의가 필요하다. 본 연구에서는 인화성의 유해화학물질 취급 시 실내 취급시설의 적정 환기율을 계산하는 새로운 합리적인 방법을 제안하였다. 연구방법: 취급시설의 바닥면적만을 기준으로 한 현행 화학물질관리법 상 계산방법과 비교하여 보다 합리적인 새로운 방법은 취급하는 유해화학물질의 물리화학적인 특성을 기반으로 계산하는 방법이다. 연구결과:물리화학적 특성을 고려하여 계산한 결과 인화성물질 178종 중 168종인 약 94%이 환기량 기준에 적합하였다. 그러나 일부 물질은 과소환기 및 과대환기를 요구하는 것으로 나타났다. 결론:본 연구를 통해 합리적인 필요환기량 산정방법을 제안하였고 이를 통해 근로자의 안전을 확보하고 생명을 보호해야 할 것이다.