• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1105-1114
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• 2021

Due to the recent surge in popularity of cryptocurrency, the threat of cryptojacking, a malicious code for mining cryptocurrencies, is increasing. In particular, web-based cryptojacking is easy to attack because the victim can mine cryptocurrencies using the victim's PC resources just by accessing the website and simply adding mining scripts. The cryptojacking attack causes poor performance and malfunction. It can also cause hardware failure due to overheating and aging caused by mining. Cryptojacking is difficult for victims to recognize the damage, so research is needed to efficiently detect and block cryptojacking. In this work, we take representative distinct symptoms of cryptojacking as an indicator and propose a new architecture. We utilized the K-Nearst Neighbors(KNN) model, which trained computer performance indicators as behavior-based dynamic analysis techniques. In addition, a K-means model, which trained the frequency of malicious script words for script similarity-based static analysis techniques, was utilized. The KNN model had 99.6% accuracy, and the K-means model had a silhouette coefficient of 0.61 for normal clusters.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.285-293
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• 2023

In this research, we embarked on a meticulous analysis of the challenges inherent in real-world scenarios relating to the durability design standards of engineered concrete structures and the assessment of carbonation durability in concrete guidelines. Our investigation brought to light substantial issues concerning constructability and quality assurance. The genesis of these problems is the exclusive application of prescribed strength to exterior walls, neglecting other elements to facilitate smoother licensing procedures. While this methodology aims to mitigate financial constraints in alignment with enhanced standards, it invariably invites complications. Furthermore, it is imperative to resolve the uncertainty surrounding durability evaluations by establishing a clear and definitive objective. Alongside this, actionable steps must be formulated to forestall the emergence of fissures between the floors of residential buildings, particularly apartment complexes. It is equally essential to tackle issues connected to application by devising a comprehensive management strategy for potential cracking during the phase of maintenance.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.34-34
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• 2021

본 연구에서는 격자기반 분포형 수문모델링을 통해 하천갈수량을 추정하고자 한다. 분포형 수문모형은 단방향흐름 알고리즘에 의한 토양 물수지식을 기반으로 개발되었으며 운동파(kinematic wave) 이론을 적용하여 지표 및 지표하 유출을 모의한다. 또한, 격자별로 수문학적 물수지요소인 차단량, 증발산량, 침투 및 침루량, 지하수충전량 등을 계산하며, 댐·보 방류량을 해당 지점 격자의 물수지에 적용할 수 있도록 개발하였다. 본 모형은 2개의 다목적댐과 3개의 다기능보가 위치한 금강유역(9,645.5 km²)에 적용하였으며, 유역 면적과 하천 유속을 고려하여 1 km × 1 km 격자를 구성하고 10분 간격으로 2013년부터 2020년까지 수문모의를 진행하였다. 모형의 입력자료로 유역 인근의 12개 기상관측소로부터 시단위 기상자료를 구축하였으며, 모형의 검보정은 일단위 관측유량(Q), 플럭스 타워 증발산량, 실측 토양수분 및 지하수위 자료를 구축하여 활용하였다. 댐 및 보 지점에 대해 Q와 1/Q로 검보정을 수행한 결과, 평균 결정계수(R²)는 댐 지점에서 0.53~0.65, 보 지점에서 0.46~0.69의 값을 나타냈으며, Nash-Shtcliffe efficiency(NSE)는 댐 지점에서 0.46~0.55, 보 지점에서 0.31~0.65의 값을 나타냈다. 공간 보정을 위해 증발산량, 토양수분, 지하수위에 대한 검보정을 수행할 예정이며, 유황곡선을 활용하여 하천차수, 토양속성 및 토지이용에 따른 하천갈수량을 분석할 예정이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.943-953
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• 2006

We investigated experimentally the static behavior of an orthotropic bridge deck which is made from glass fiber reinforced polymer (GFRP) and polyurethane foam. The bridge deck consists of many unit cells with rectangular holes which are filled with the foam to improve its structural behavior in its weak axis. It is found that although the elastic modulus of the foam compared to that of the GFRP is about the order of, the structural behaviors in the weak axis such as nominal strength, stiffness, etc. are greatly improved. Owing to the low mass density of the foam used in this study, the bridge deck is still light enough with the improved structural properties. Webs of the cells filled with the foam did not significantly contribute to the strength development of the deck. However, the propagation of a crack initiated in a cell is caught by the webs and limited to the inside of that cell only, which makes the load-displacement behavior of the foam-filled GFRP deck less brittle.

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.243-250
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• 2010

This paper proposes a spectral modeling of Korean traditional instrument, Haegeum, using cepstral analysis to naturally describe Haegeum sounds varying with time. To get a precise result of cepstral analysis, we set the frame size to 3 periods of input signal and more cepstral coefficients are used to extract formants. The performance is enhanced by flexibly controlling the cutoff frequency of bandpass filter depending on the resonances in the synthesis process of sinusoidal components and the deleting peaks remained in the residual signal. To detect the change of pitch, we divide the input frames into silence, attack, and sustain region and determine which region the current frame is involved in. Then, the proposed method readjusts the frame size according to the fundamental frequency in the case of the current frame is in attack region and corrects the extraction errors of the fundamental frequency for the frames in sustain region. With these processes, the synthesized sounds are much more similar to the originals. The evaluation result through the listening test by a Haegeum player says that the synthesized sounds are almost similar to originals (96~100 % similar to the original sounds).

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.363-368
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• 2024

Steel structures used in marine environments, such as ships, offshore structures or sub-structures in wind power generation facilities are prone to corrosion. In this study, the corrosion fatigue crack propagation characteristics due to the environmental load are examined by experiment at -1050 mV vs. SCE, which is equivalent to the anti-corrosion potential of zinc anodes that are widely used as sacrificial anodes. In this study, for this purpose, an experimental study is conducted on the effect of cathodic protection on the propagation of fatigue cracks in the seawater environment under the condition of -1050 mV vs. SCE, considering the wave period in synthetic seawater. Cathodic protection prevents corrosion; however, excessive protection generates hydrogen through chemical reactions as well as calcareous deposits. The fatigue crack propagation rate appeared to be faster than the rate in a seawater corrosion environment at the early stages of the experiment. As the crack length and stress intensity factor K increased, the crack propagation rate became slower than the fatigue crack propagation rate in seawater. However, the crack growth rate was faster than that in the atmosphere.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4D
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• pp.305-311
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• 2012

With the rapid deployment of hipass$^{(R)}$, the congestion is inevitable due to the operation of the hipass lane system. Recently, SMART Highway project have developed a multi-lane mainline tolling system, called SMART Tolling system. To analyze the effectiveness of the system in terms of capacity, this study tries to estimate the capacity and its improvement of multi-lane tolling system based on current hipass$^{(R)}$ data. The methodology uses the saturation time headway. This follows three steps; 1) estimate the saturation time headway, using hipass$^{(R)}$ data, and capacity. 2) estimate two factors (the first one is dividing the one side lane width and lateral clearance factor ($f_w$) into two side one, the second one is dividing the capacity of hipass lane operating a circuit breaker into the capacity of hipass lane not operating, the last one is increasing factor of lane width). 3) calculate the capacity of multi-lane mainline tolling system. The results of method produced 2172~2187 veh/hour as smart tolling capacities, respectively. Those are higher about 370 veh/hour than the values from existing literature reviews. Additionally, saturation time headways were identified as lower by 0.5 seconds/veh than existing headways based on hi-pass$^{(R)}$ based one, which naturally implies the improvement in capacity. Some limitations and future research agenda have also been discussed.

• Proceedings of the Korean DIstribution Association Conference
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• 2001.11b
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• pp.145-163
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• 2001

최근 인터넷 상거래가 급속히 확산되면서 기업의 경쟁이 실물세계와 가상세계에서 발생하는 현상이 전개되고 있다. 즉, 유통경로의 측면에서 볼 때 기존의 물리적 세계에 존재하는 전통적인(오프라인) 유통경로와 사이버공간에 존재하는 가상(온라인) 유통경로가 서로 경쟁하는 형국이 벌어지고 있는 것이다. 유통경로간 경쟁의 중심부에는 고객이 자리잡고 있다. 어떤 경로든 소비자의 욕구를 정확히 파악하고, 이들에게 최상의 유통서비스를 제공하는 경로는 생존·번영할 수 있을 것이다. 사실 현재 진행되고 있는 논의들과 현상들을 볼 때, 어느 한 유통경로가 다른 유통경로를 완전히 대체하는 제로섬 게임의 양상은 나타나고 있지 않다. 즉, 상당기간 두 유통경로는 상호 병존할 것으로 보인다. 본 연구는 이러한 점에 초점을 맞추어 이들 두 경로가 자신들만의 차별화된 경쟁우위를 가지고 생존할 수 있는 마케팅전략을 구상하기 위해 시도되었다. 이러한 전략을 제시하기 위해서는 우선 이들 두 경로상에서 소비자의 구매(쇼핑)행동은 어떻게 다른가에 대한 비교연구가 선행되어야 할 것이다. 본 연구는 온라인 유통경로와 오프라인 유통경로에서 소비자 구매행동의 차이를 비교분석 하는데 그 목적을 두고 있다. 특히 제품유형별로 온라인과 오프라인에서 구매속성중요도가 어떻게 달라지는가를 확인. 검증해 보기 위해 시도되었다. 캐주얼의류, 여행상품, 음악CD를 가지고 인터넷 사용자 500명을 대상으로 온라인조사를 실시한 결과, 온라인과 오프라인에서 구매속성 중요도에는 유의한 차이가 나타났다. 이 결과를 토대로 오프라인 매장과 온라인 매장이 어떻게 차별화해야 하는가에 대한 시사점을 제시하였다.통계적인 차이가 있었다(P<0.05). 계육내 CLAisomer는 1, 2, 3% 급여구에서 각각 12.23, 18.74, 25.67 mg/g으로 처리구간에 현저한 차이를 보였다(P<0.05). 본 연구의 결과 CLA의 급여는 SBO와 CT에 비하여 증체량을 개선하고 혈중HDL을 높여주는 경향을 보였지만 ND항체가는 개선되지 못하였다.으며, 그 효과는 농도에 의존적이었다, 고콜레스테롤 투여군(HC)의 분변 중 총 지질과 중성지방 농도는 정상대조군(C)에 비해 다소 높았고, 총 콜레스테롤의 경우는 유의적으로 높게 나타났다. 그러나 뽕잎첨가군(HC5M과 HC10M)의 총 지질, 중성지방 및 콜레스테롤 농도는 콜레스테롤 투여군(HC)에 비해 분변으로 배설량이 증가하는 현상을 보였다. 이상의 결과를 살펴보면 뽕잎 분말은 고콜레스테롤식이를 섭취하는 경우 혈청과 간장의 지질수준은 떨어뜨리고, 분변중 지질배설량을 상승시키는 효과가 현저한 것으로 보인다.둘째. 1990년대 한국과 미국 패션시장의 가격과 품질간의 상관계수의 범위는 제품군별. 산업범주별 로 상이한 분포를 보이고 있었다. 패션제품군별로 보 면, 한국의 경우는 가장 높은 '여행용가방(r = 0.707)' 에서 가장 낮은 '자외선 차단화장품(r = -0.58)'까지, 그리고 미국 패션제품군의 상관계수의 범위는 '팬티 스타킹'의 0.820에서 '남성용 런닝슈즈'의 -0.472까지의 분포를 나타냈다. 마지막으로, 제품의 가격과 품질에 대한 정보를 소비자가 알 경우 얻을 수 있는 소비자의 구매이득 을 추산한 결과 패션제품시장에서 완전한 품질정보를 가지고 있다고 가정한 '현명한 사람'은, 최고가격의 제품만을

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.18-23
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• 1999

A numerical model of flow velocity in the standing water system is presented. This model(RMA-2), based on the 2-dimensional unsteady momentum and continuity equations, uses finite element techniques to simulate the distribution of velocity over a spatial location of lakes. The present model represents an improvement over existing numerical water quality models in that it can model the unsteady state and can, therefore, cope with time with a spatial location of standing waters such as lakes and large reservoirs. The model thus allows the engineer to do more accurate estimation of water flows and thus water qualities in standing waters where directions and velocities of the flow become more important for the simulation of the water quality than in running waters. Tests for the data collected in the lake "Paldang" indicates that the model works well under limited circumstances. However, to be more accurate estimation of velocity with the present model, accumulation of data for the measurement of velocities and renovation of geometrical conditions of the lake would be needed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.21-27
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• 2004

In this paper, millimeter-wave monolithic integrated circuit(MIMIC) low noise amplifier(LNA) for V-band, which is applicable to 60 GHz wireless local area network(WLAN), was fabricated using the high performance 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate pseudomorphic high electron mobility transistor(PHEMT). The DC characteristics of PHEMT are drain saturation current density(Idss) of 450 mA/mm and maximum transconductance(gm, max) of 363.6 mS/mm. The RF characteristics were obtained the current gain cut-off frequency(fT) of 113 GHz and the maximum oscillation frequency(fmax) of 180 GHz. V-band MIMIC LNA was designed using active and passive device library, which is composed of 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate PHEMT and coplanar waveguide(CPW) technology. The designed V-band MIMIC LNA was fabricated using integrated unit processes of active and passive device. The measured results of V-band MIMIC LNA are shown S21 gain of 21.3 dB, S11 of -10.6 dB at 60 GHz and S22 of -29.7 dB at 62.5 GHz. The measured result of V-band MIMIC LNA was shown noise figure (NF) of 4.23 dB at 60 GHz.