• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.206-208
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• 2008

In this paper, the two-stage DC-DC converter is proposed to make the control simple and to boost the low input voltage in the fuel cell generating system. The low efficiency of the conventional power converter is caused by a characteristic of the low-voltage and high-current in the fuel cell generating system. High-frequency transformer is needed to block the noise and to guarantee the safety of cell and load as a magnetically insulation. The proposed two-stage DC-DC converter for a fuel cell generation is more efficient than the traditional one-stage converter and easy to control. The design of a high-frequency transformer is also simple. Finally, the utility of the proposed converter is proved by the simulations and experiments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.436-437
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• 2007

Organic light-emitting diodes (OLEDs) were fabricated with the electron dominant complex, 4,7-diphenyl-1, 10-phenanthroline (Bphen) into the traditional electron transporting material of tris (S-hydroxyquinoline) aluminum $(Alq_3)$, neat $Alq_3$ and Bphen as electron-transporting layers (ETLs), respectively. Use of the Bphen material results in efficient electron injection and transport, allowing for high luminous efficiency devices. The devices with neat $Alq_3$(Device1), 1:1 mixed $Alq_3$ : Bphen(Device2), and Bphen(Device3) have efficiency of 15.3cd/A, 16.9cd/A, 20.9cd/A, respectively, at $20\;mA/cm^2$. The efficiency characteristic of device with Bphen is best, but the device that is satisfied high efficiency and stability at once is observed in Device2.

• Natural Product Sciences
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• 제16권2호
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• pp.107-110
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• 2010

Curcuma caesia Roxb. (Zingiberaceae) is commonly known as 'Black turmeric'. In India it grows in West Bengal, Madhya Pradesh, Orissa, Bihar, North-East and Uttar Pradesh and is widely used by ethnic communities for various ailments. Rhizomes of the plant are used for sprains and bruises and are also employed in cosmetics. In West Bengal it is an important place in traditional system of medicine and is also used as a substitute for turmeric in fresh stage. Present communication deals with the detailed pharmacognostical evaluation of the rhizome sample. Inner part of the rhizome is bluish-black in colour and emits a characteristic sweet smell, due to the presence of essential oil. On steam distillation the rhizome yields an essential oil rich in camphor. A detailed HPTLC studies has been carried out for quantitative evaluation of active marker component. HPTLC, physico-chemical, morphological and histological parameters presented in this paper may be proposed as parameters to establish the authenticity of C. caesia rhizome and may possibly help to differentiate the drug from its other allied species.

• 한국소음진동공학회논문집
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• 제26권6_spc호
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• pp.651-659
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• 2016

Condition monitoring (CM) encounters a large data problem due to sensors that measure vibration data with a continuous, and sometimes, high sampling rate. In this study, compressive sensing approaches for condition monitoring are proposed to demonstrate the efficiency in handling a large amount of data and to improve the damage detection capability of the current condition monitoring process. Compressive sensing is a novel sensing/sampling paradigm that takes much fewer samples compared to traditional sampling methods. For the experiments a built-in rotating system was used and all data were compressively sampled to obtain compressed data. Optimal signal features were then selected without the reconstruction process and were used to detect and classify damage. The experimental results show that the proposed method could improve the data processing speed and the accuracy of condition monitoring of rotating systems.

• Journal of Preventive Medicine and Public Health
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• 제42권6호
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• pp.349-355
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• 2009

Biomarkers are characteristic biological properties that can be detected and measured in a variety of biological matrices in the human body, including the blood and tissue, to give an indication of whether there is a threat of disease, if a disease already exists, or how such a disease may develop in an individual case. Along the continuum from exposure to clinical disease and progression, exposure, internal dose, biologically effective dose, early biological effect, altered structure and/or function, clinical disease, and disease progression can potentially be observed and quantified using biomarkers. While the traditional discovery of biomarkers has been a slow process, the advent of molecular and genomic medicine has resulted in explosive growth in the discovery of new biomarkers. In this review, issues in evaluating biomarkers will be discussed and the biomarkers of environmental exposure, early biologic effect, and susceptibility identified and validated in epidemiological studies will be summarized. The spectrum of genomic approaches currently used to identify and apply biomarkers and strategies to validate genomic biomarkers will also be discussed.

• 패션비즈니스
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• 제12권3호
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• pp.62-71
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• 2008

Costume elements are closely related with human living environment and also play an important role in the costume patterns. The East and the West have influenced and adopted each other's culture through mutual trade, which are well reflected in costume patterns and textile patterns. These days world wide fashion shows the designs applying costume details of the East and the West, which is much affected by the orientalism. The purpose of this study is to compare the sleeve patterns which take an important part in women's costume design of the Joseon Dynasty and the European Monarchy in the 16th century. Korean women's costume showed sleeves in rectangular shape with same width and long length, together with cuffs. Later they changed to diagonal shape of getting narrower toward the wrist. Western women's costume showed sleeves with puff and slash patterns. Then they were classified into French, British and Spanish styles which were getting narrower toward the wrist. Later they adopted the shape of leg of mutton which was puffed in middle and narrower toward the wrist. I n Korea and Europe, they showed respective changes in sleeve patterns, but also similarity of getting narrower toward the wrist. The East and the West are now exchanging their culture in every aspect such as politics, economics and social matters. Costume fashion is not an exception. The characteristic designs of traditional costumes are shown on global fashion, which is influenced by the orientalism.

• 한국식생활문화학회지
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• 제11권1호
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• pp.97-106
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• 1996

A literature on Korean rice cakes by ingredients and preparation methods was reviewed with published literatures in Korea from 1950 to 1995. The result were as followed; 1. The 46 volumes about preparation of Korean rice cakes were reported. There were 32 steamed (Jeung-byung), 6 pounded (Do-byung), 4 fried (Yu-jeon-byung), and 4 boiled Korean rice cakes (Kyung-Dan). This result showed that steamed Korean rice cake was the most frequently studied among any other kinds of Korean rice cakes. 2. The reports on preparation of Korean rice cakes were rare during $1950's{\sim} 1960's$. In 1970's, there were few papers about basic study for Korean rice cakes. And it was reached 8 volumes of steamed, each 1 volume of fried or boiled Korean rice cakes. From 1990's, the more scientific researches were progressed vigorously so reached 11 volumes till 1995 but it was limited to Solgi and Jeungpyun etc. This result shows that the experiment for Korean rice cake was not various. 3. The preceded studies for Korean rice cake were investigated to see texture, sensory, quality characteristic and effect of substitutes added to original ingredients.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.397-400
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• 2008

기존의 자연점화특성을 지니는 추진제는 성능이 높은 대신 독성이 있으며 다루기 어렵고, 환경에 유해한 단점을 지닌다. 이에 따른 대안으로 과산화수소의 촉매분해 후에 발생되는 고온의 산소와 수증기를 이용한 자연점화 방식이 있다. 이 논문에서는 자연점화 방식의 과산화수소/케로신 추력기를 설계하기 위한 기초연구를 수행하기 위해 자연점화특성을 연구하였다. 추력기의 형상변수로 노즐 목의 면적을 달리하여 연소챔버와의 단면적 비인 수축비를 달리하였으며, flame holder의 유 무, 과산화수소와 케로신의 가압압력에 따른 점화특성 및 연소안정성을 관찰하였다. 그 결과, 대부분의 경우에 자연점화를 관찰할 수 있었으나, 가압압력의 조건에 따라 연소 안정성에는 큰 변화가 있음을 확인할 수 있었다.

• Journal of Information Processing Systems
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• 제17권4호
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• pp.851-865
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• 2021

Enterprise networks in the PyeongChang Winter Olympics were hacked in February 2018. According to a domestic security company's analysis report, attackers destroyed approximately 300 hosts with the aim of interfering with the Olympics. Enterprise have no choice but to rely on digital vaccines since it is overwhelming to analyze all programs executed in the host used by ordinary users. However, traditional vaccines cannot protect the host against variant or new malware because they cannot detect intrusions without signatures for malwares. To overcome this limitation of signature-based detection, there has been much research conducted on the behavior analysis of malwares. However, since most of them rely on a sandbox where only analysis target program is running, we cannot detect malwares intruding the host where many normal programs are running. Therefore, this study proposes a method to detect malware variants in the host through logs rather than the sandbox. The proposed method extracts common behaviors from variants group and finds characteristic behaviors optimized for querying. Through experimentation on 1,584,363 logs, generated by executing 6,430 malware samples, we prove that there exist the common behaviors that variants share and we demonstrate that these behaviors can be used to detect variants.

• 아태비즈니스연구
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• 제11권4호
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• pp.37-48
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• 2020

Purpose - This study empirically investigates whether the risk property included in fat-tails of return distributions is systematic or unsystematic based on the devised statistical methods. Design/methodology/approach - This study devised empirical designs based on two traditional methods: principal component analysis (PCA) and the testing method of portfolio diversification effect. The fatness of the tails in return distributions is quantitatively measured by statistical probability. Findings - According to the results, the risk property in the fat-tails of return distributions has the economic meanings of eigenvalues having a value greater than 1 through PCA, and also systematic risk that cannot be removed through portfolio diversification. In other words, the fat-tails of return distributions have the properties of the common factors, which may explain the changes of stock returns. Meanwhile, the fatness of the tails in the portfolio return distributions shows the asymmetric relationship of common factors on the tails of return distributions. The negative tail in the portfolio return distribution has a much closer relation with the property of common factors, compared to the positive tail. Research implications or Originality - This empirical evidence may complement the existing studies related to tail risk which is utilized in pricing models as a common factor.