• 한국지열·수열에너지학회논문집
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• 제17권1호
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• pp.14-22
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• 2021

Drilling equipment is an essential part used in various fields such as construction, mining, etc., and it has drawn increasing attention in recent years. The drilling method is generally divided into three types. There are a top hammer method that strikes on the ground, a DTH (Down-The-Hole) method that directly strikes a bit in an underground area, and a rotary method that drills by using rotational force. Among them, the DTH method is most commonly used because it enables efficient drilling compared to other drilling methods. In the conventional DTH hammer, the valve between the piston and the bit is opened and closed using a face to face method. In order to improve the power of the DTH hammer, a DTH hammer with foot valve which is capable of instantaneous opening and closing is used in the drilling field. In this study, we designed a lab-scale DTH hammer with the foot valve, and manufactured an evaluation device for the experiment of the DTH hammer. In addition, we analyzed the performance of the DTH hammer adopted with foot valve according to the pressure range of 3-10 bar. As a result, the internal pressure distribution in the DTH hammer was experimentally analyzed, and then, the movement of the piston according to the pressure was predicted. We believe that this study provides the useful results to explain the performance characteristics of the DTH hammer with the foot valve.

• 정보보호학회논문지
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• 제17권4호
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• pp.61-74
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• 2007

공통기준(CC) 평가체계에서 평가신청인과 평가자는 평가프로젝트를 계약할 때 정보보호시스템의 평가비용과 기간을 산정해야한다. 본 논문에서는 2003년과 2005년에 수행한 연구 결과들을 분석하였으며, 연구 결과의 일부분을 활용하여, CC 2.3과 CC 3.1의 평가보증수준($EAL1{\sim}EAL7$)간의 상대적 평가업무량 배율을 실험조사적으로 산정했다. 또한, 각 보증 컴포넌트에 대해 '개발자요구사항', 조정된 '증거요구사항', '평가자요구사항'으로부터 배율을 산정하였고, 특히, 2003년에 KISA 평가 자료로부터 구한 평가자요구사항별 업무량배율을 사용했다. 본 연구의 결과는 새로운 CC 3.1 평가체계에서 특정한 EAL과 제품유형에 대한 평가비용과 기간을 예측해야하는 평가신정인과 평가프로젝트 관리자에게 유용할 것이다.

• 디지털융복합연구
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• 제19권6호
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• pp.309-314
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• 2021

디즈니 애니메이션은 미국의 문화와 예술의 일부라고 할 수 있다. 미국의 사회·문화의 변화에 따라 디즈니 애니메이션에 등장하는 여성 캐릭터의 성격과 사회적 위상의 변화를 볼 수 있다. 특히 2000년 이후에 발표된 디즈니 애니메이션 작품에서는 여성과 남성의 사회적 능력과 지위에 대하여 대등 또는 평등하게 표현된 수많은 작품이 발표되었다. 본 연구에서는 20세기와 21세기 여성 캐릭터의 특징을 비교하고 <겨울왕국2>의 은유적인 방법으로 여성 이미지를 표현한 엘사와 안나의 캐릭터를 분석하였다. 또한 의상 및 색채의 다양한 스타일링의 특징과 의미를 연구하였다. 본 논문은 여성 캐릭터의 성평등 이미지 구축 시 필요한 디자인 요소를 제시하였으며 향후 애니메이션 산업계와 학계에 유용한 연구자료로 활용되길 기대한다.

• 한국응용과학기술학회지
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• 제38권1호
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• pp.263-270
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• 2021

삼채는 Allium 속 식물로써, 항산화, 항염 및 항균 등에 대한 선행연구가 실시되어왔지만, 정유 추출로써의 연구는 미비한 실정이다. 그에 본 연구는 삼채 잎, 뿌리, 통 부위에 대한 정유 추출에 따른 GC-MSD, 삼채잎의 세포독성, 항산화, 항염을 확인하여 화장품 소재로서의 가능성을 확인하였다. 삼채잎, 뿌리, 통부위의 정유추출 수율은 0.01, 0.02, 0.01%로 확인되었고, GC-MSD 향기성분을 분석한 결과 삼채잎 정유의 주요 성분은 Diallyl trisulfide(34.02%)와 Methyl allyl trisulfide(25.14%)으로 나타났다. 세포독성이 확인되지 않은 10%의 농도에서 NO 생성 39.69%억제, DPPH 라디칼 소거활성 88.26%를 보였다. 이를 통하여 삼채 잎 정유는 화장품 및 식품 산업분야에서 항산화 및 항염 효능이 있는 원료로서 유용하게 활용 가능성을 제시한다.

• 융합정보논문지
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• 제12권1호
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• pp.144-152
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• 2022

본 연구에서는 생태교란종으로 지정되어 대량으로 방제되는 영국갯끈풀의 에탄올 추출물을 활용하여 여러가지 생리활성을 평가하고 화장품 원료로서의 활용 가능성을 확인하고자 하였다. 항산화 활성은 라디컬 소거법인 DPPH와 ABTS assay 및 환원력을 통한 FRAP과 같은 화학적 방법으로 조사한 결과, 영국갯끈풀 지상부 에탄올 추출물의 항산화 활성이 우수하였다. 각 추출물 농도 0.5 mg/mL 이하 조건에서 RAW264.7 cell과 NHDF cell에 대한 세포독성은 관찰되지 않았다. LPS로 활성화 된 RAW264.7 세포에서 증가된 염증매개물질 NO와 사이토카인 생성량은 지하부 에탄올 추출물에 의해 뚜렷하게 감소되었다. 또한 NHDF cell을 지상부와 지하부 두 추출물로 처리하여 collagen 합성과 피부 수분 유전자 발현을 조사한 결과 높은 항주름 및 보습 효능을 나타냈다. 이와 같은 결과를 통하여 영국갯끈풀 에탄올추출물은 기능성화장품의 생리활성 물질에 대한 유용한 바이오 자원으로서의 활용 가능성이 우수함을 확인하였다.

• 한국정보통신학회논문지
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• 제26권4호
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• pp.612-623
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• 2022

실시간으로 유동인구를 계측하는 기술은 다양한 산업 분야에서 공간 밀집도에 대한 통찰력을 제공하여 더 좋은 서비스 환경을 만들어준다. 이에 따라 여러 기업과 학계에서는 특정 공간의 유동인구 데이터를 계측하기 위해 오랫동안 다양한 연구를 시도해왔으며, 최근에는 스마트시티와 디지털트윈의 일환으로 Wi-Fi 신호를 활용한 유동인구 분석 사업화가 더욱 활발한 추세이다. 본 논문에서는 사람들이 소지한 스마트폰으로부터 수집되는 MAC-address 값 기반의 유동인구 추정 방법을 제시하는데, 추정값의 정확도를 분석하기 위해 Real MAC-address와 Random MAC-address 값을 구분한 뒤, Real MAC-address가 추출된 실제 스마트폰 기기 수와 CCTV 화면에 집계된 사람 수를 비교하는 실험을 진행한다. 그 결과 두 데이터 간의 유사한 상관 계수가 나타났다. 이러한 결과에 근거하여 MAC-address 분류를 통한 Wi-Fi Probe Request 기반 유동인구 분석 방법을 제시한다.

• 대한안전경영과학회지
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• 제24권1호
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• pp.31-38
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• 2022

The most common symptoms of COVID-19 are high fever, cough, headache, and fever. These symptoms may vary from person to person, but checking for "fever" is the government's most basic measure. To confirm this, many facilities use thermographic cameras. Since the previously developed thermographic camera measures body temperature one by one, it takes a lot of time to measure body temperature in places where many people enter and exit, such as multi-use facilities. In order to prevent malfunctions and errors and to prevent sensitive personal information collection, this research team attempted to develop a facial recognition thermographic camera. The purpose of this study is to compensate for the shortcomings of existing thermographic cameras with disaster safety IoT integrated solution products and to provide quarantine systems using advanced facial recognition technologies. In addition, the captured image information should be protected as personal sensitive information, and a recent leak to China occurred. In order to prevent another case of personal information leakage, it is urgent to develop a thermographic camera that reflects this part. The thermal imaging camera system based on facial recognition technology developed in this study received two patents and one application as of January 2022. In the COVID-19 infectious disease disaster, 'quarantine' is an essential element that must be done at the preventive stage. Therefore, we hope that this development will be useful in the quarantine management field.

• Journal of Audiology & Otology
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• 제24권4호
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• pp.167-173
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• 2020

Background and Objectives: Top-down restoration of distorted speech, tapped as phonemic restoration of speech in noise, maybe a useful tool to understand robustness of perception in adverse listening situations. However, the relationship between phonemic restoration and speech perception in noise is not empirically clear. Subjects and Methods: 20 adults (40-55 years) with normal audiometric findings were part of the study. Sentence perception in noise performance was studied with various signal-to-noise ratios (SNRs) to estimate the SNR with 50% score. Performance was also measured for sentences interrupted with silence and for those interrupted by speech noise at -10, -5, 0, and 5 dB SNRs. The performance score in the noise interruption condition was subtracted by quiet interruption condition to determine the phonemic restoration magnitude. Results: Fairly robust improvements in speech intelligibility was found when the sentences were interrupted with speech noise instead of silence. Improvement with increasing noise levels was non-monotonic and reached a maximum at -10 dB SNR. Significant correlation between speech perception in noise performance and phonemic restoration of sentences interrupted with -10 dB SNR speech noise was found. Conclusions: It is possible that perception of speech in noise is associated with top-down processing of speech, tapped as phonemic restoration of interrupted speech. More research with a larger sample size is indicated since the restoration is affected by the type of speech material and noise used, age, working memory, and linguistic proficiency, and has a large individual variability.

• Journal of Information Science Theory and Practice
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• 제10권1호
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• pp.1-17
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• 2022

The article reports the results of an investigation on the practice of providing digital scholarship services at Vietnam National University Ho Chi Minh City, Vietnam. This study is part of an ongoing research project entitled Developing a digital scholarship service framework for universities at Vietnam National University Ho Chi Minh City. It employed a qualitative research approach through in-depth interviews with 31 individuals who are university managers, library managers, lecturers, and postgraduate and undergraduate students from six member universities and Central Library of Vietnam National University Ho Chi Minh City. Research results show that some digital scholarship services have been provided at Vietnam National University Ho Chi Minh City. However, they have not been yet systematically implemented and have not met users' needs. Lack of needed resources such as space, technology infrastructure, human resources, finance, and stakeholder support are among major challenges in developing digital scholarship services. The management of existing digital scholarship services is fragmented without a clear policy for developing digital scholarship and supporting services. The study contributes to the existing knowledge by adding substantially to current understanding of the practice of providing digital scholarship services in Vietnam's universities in the transition period, from state control to autonomy, which has not been much addressed in previous research. Furthermore, this study can be a useful reference for higher education institutions in developing countries regarding implementation of digital scholarship services.

• 대한청각학회지
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• 제24권4호
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• pp.167-173
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• 2020

Background and Objectives: Top-down restoration of distorted speech, tapped as phonemic restoration of speech in noise, maybe a useful tool to understand robustness of perception in adverse listening situations. However, the relationship between phonemic restoration and speech perception in noise is not empirically clear. Subjects and Methods: 20 adults (40-55 years) with normal audiometric findings were part of the study. Sentence perception in noise performance was studied with various signal-to-noise ratios (SNRs) to estimate the SNR with 50% score. Performance was also measured for sentences interrupted with silence and for those interrupted by speech noise at -10, -5, 0, and 5 dB SNRs. The performance score in the noise interruption condition was subtracted by quiet interruption condition to determine the phonemic restoration magnitude. Results: Fairly robust improvements in speech intelligibility was found when the sentences were interrupted with speech noise instead of silence. Improvement with increasing noise levels was non-monotonic and reached a maximum at -10 dB SNR. Significant correlation between speech perception in noise performance and phonemic restoration of sentences interrupted with -10 dB SNR speech noise was found. Conclusions: It is possible that perception of speech in noise is associated with top-down processing of speech, tapped as phonemic restoration of interrupted speech. More research with a larger sample size is indicated since the restoration is affected by the type of speech material and noise used, age, working memory, and linguistic proficiency, and has a large individual variability.