• 센서학회지
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• 제29권5호
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• pp.303-311
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• 2020

Nondispersive infrared CO₂ gas sensor was developed after the simulation of optical cavity structure and assembling the optical components: IR source, concave reflectors, Fresnel lens, a hollow disk, and IR detectors. By placing a hollow disk in front of reference IR detector, the output voltages are almost constant value, near to 70.2 mV. The absorbance of IR light, F_a, shows the second order of polynomial according to ambient temperatures at 1,500 ppm. The differential output voltages and the absorbance of IR light give a higher accuracy in estimations of CO₂ concentrations with less than ± 1.5 % errors. After implementing the parameters that are dependent upon the ambient temperatures in microcontroller unit (MCU), the measured CO₂ concentrations show high accuracies (less than ± 1.0 %) from 281 K to 308 K and the time constant of developed sensor is about 58 sec at 301 K. Even though the estimation errors are relatively high at low concentration, the developed sensor is competitive to the commercial product with a high accuracy and the stability.

• 전기학회논문지
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• 제62권5호
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• pp.717-722
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• 2013

The wastewater reclamation and reusing system has been rising as an alternative of water resource exhaustion that the whole world is experiencing. In order to be able to bring about improvement of the existing wastewater reclamation and reusing system, this research has developed of Conversion-Human Machine Interaction (C-HMI) based real-time control and monitoring system such as a sensor module and gate module, web monitoring system. This system was communication almost-error-free in various environment and situation. As a result, we have achieved our goal that has to doing work correctly as a sensor and gateway module that communication error is less than 0.2% throughout the embodied system and add that it can be easily controled and configured as an interface equipment to a complex sensor of water quality. According to this, the construction of a database capable of analyzing and assessing collection, storage and various elements of reliable water quality and flow rate data can be possible.

• Journal of information and communication convergence engineering
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• 제15권1호
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• pp.53-61
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• 2017

The preferred feature selection methods for text classification are filter-based. In a common filter-based feature selection scheme, unique scores are assigned to features; then, these features are sorted according to their scores. The last step is to add the top-N features to the feature set. In this paper, we propose an improved global feature selection scheme wherein its last step is modified to obtain a more representative feature set. The proposed method aims to improve the classification performance of global feature selection methods by creating a feature set representing all classes almost equally. For this purpose, a local feature selection method is used in the proposed method to label features according to their discriminative power on classes; these labels are used while producing the feature sets. Experimental results obtained using the well-known 20 Newsgroups and Reuters-21578 datasets with the k-nearest neighbor algorithm and a support vector machine indicate that the proposed method improves the classification performance in terms of a widely known metric ($F_1$).

• KIEAE Journal
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• 제13권6호
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• pp.93-98
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• 2013

The purpose of this study is to analyze the rate of opening windows that makes residents of a flat-type apartment feel pleasant in summer time. A few conditions were simulated on the wind flow that pass through internal and external spaces of the flat-type apartment, utilizing CFX program. The simulation was made with the criteria for the rates of opening window at 20%, 50%, 70% and 100%. When the rate of window opening was more 50%, the wind speed(more than 1m/s) that makes the residents feel pleasant was observed in more 60% of the internal space. When the all windows of the apartments were opened, the heat island phenomenon was almost disappeared and the pleasant wind flow was more evenly distributed in the external spaces. If residents of apartments recognize the result of this study and practice in agrement on opening windows in summer, it is expected to contribute to minimizing the energy consumption for air conditioning.

• 한국인터넷방송통신학회논문지
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• 제16권3호
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• pp.129-135
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• 2016

저시력인들을 위한 기존 시각 향상 장치들이 많이 있다. 이 장치는 주로 확대경 역할이 대부분이고, 고가이다. 저시력 원인으로는 다양한 증상에 기인한다. 시력 향상을 위해서는 영상의 확대, 밝기, 대비를 조절할 필요가 있다. 따라서 시력 향상 휴대용 마이크로 디스플레이 구동 드라이버 및 장치를 개발한다. 이 장치의 4가지 기본 원리는 영상 확대, 특정 색 조절, BLU로 밝기 조절, 프리즘에 의한 시축 개선이다. 제안된 HMVED 장치의 임상 실험이 실시되었다. 결과적으로 기존 장치에 비해서 수혜 효과가 돋보였으며 본 장치는 저중량, 저가, 휴대성이 용이하므로 저시력인의 삶의 질 향상에 도모한다.

• International journal of advanced smart convergence
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• 제7권2호
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• pp.7-21
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• 2018

The author studied the process of unifying Hanja variant groups of Korea and China for LGR (Label Generation Rule) of Internet Top-Level Hangeul Hanja Domain and possible confusion between Hangeul syllable and Hanja character. Among 3518 Chinese variant groups, Korea and China need not review variant groups which include no or just one Korean Hanja character. Korea and China reviewed 304 Chinese variant groups (9% of the 3518 Chinese variant groups) which include two or more Korean Hanja characters. By doing so, Korea and China succeeded in efficiently unifying variant groups. Unification process of variant groups which is the main core of Korea-China coordination and almost final unification result is summarized in this paper. In addition, the author analyzed systematically whether some Hanja character could be confused with a Hangeul syllable and obtained a good result which was not expected at the beginning. Probably this kind of systematic analysis has not been performed in the past and seems the first attempt, which is one of the contributions of this paper. The author also reviewed how to express K-LGR in XML for submission to ICANN.

• 한국멀티미디어학회논문지
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• 제9권1호
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• pp.119-126
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• 2006

멀티 프로세서 시스템에서 스케쥴링은 매우 중요한 부분이지만, 최적의 해를 구하는 것이 복잡하여 최근 다양한 휴리스틱 방법들에 의한 스케쥴링 알고리즘들이 제안되고 있다. 본 논문에서는 유전 알고리즘을 이용한 새로운 스케쥴링 알고리즘을 제시한다. 또한, 해를 구하는 과정에서 시뮬레이티드 어닐링 (simulated annealing)의 확률을 이용하여 유전 알고리즘의 성능을 개선시킨다. 제시된 알고리즘은 태스크들의 최종 수행 완료 시간 (makespan)을 최소화하는 것을 목표로 한다. 모의 실험을 통하여 제시된 알고리즘이 다른 알고리즘보다 최종 수행 완료 시간이 작음을 확인할 수 있었다.

• 한국멀티미디어학회논문지
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• 제18권2호
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• pp.199-206
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• 2015

Since security vulnerabilities newly discovered in a popular Web browser immediately put a number of users at risk, urgent attention from developers is required to address those vulnerabilities. Analysis of characteristics in the Web browser vulnerabilities can be used to assess security risks and to determine the resources needed to develop patches quickly to handle vulnerabilities discovered. So far, being a new research area, the quantitative aspects of the Web browser vulnerabilities and risk assessments have not been fully investigated. However, due to the importance of Web browser software systems, further detailed studies are required related to the Web browser risk assessment, using rigorous analysis of actual data which can assist decision makers to maximize the returns on their security related efforts. In this paper, quantitative software vulnerability analysis has been presented for major Web browsers with respect to the Common Vulnerability Scoring System. Further, vulnerability discovery trends in the Web browsers are also investigated. The results show that, almost all the time, vulnerabilities are compromised from remote networks with no authentication required systems. It is also found that a vulnerability discovery model which was originally introduced for operating systems is also applicable to the Web browsers.

• Journal of information and communication convergence engineering
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• 제8권6호
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• pp.690-696
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• 2010

Web-based virtual collaboration is increasingly gaining popularity in almost every area in our society due to the fact that it can bridge the gap imposed by time and geographical constraints. However, in medical field, such collaboration has been less popular than other fields. Some of the reasons were timeliness, security, and preciseness of the information they are dealing with. In this paper, we are proposing a web-based distributed medical collaboration system called Virtual Collaboration System for Medicine (VCSM) for medical doctors that meet the needs. The proposed system consists of two parts - multimedia presentation and recordable virtual collaboration. The former supports synchronized multimedia presentation using Synchronous Multimedia Integration Language (SMIL.) It allows synchronization of the contents of a PowerPoint presentation file and a video file. The presentation may be provided to the participants before the discussion begins. Next, in the virtual collaboration stage, participants can use text along with associated symbols during the discussion over the presented medical images. The symbols such as arrows or polygons can be set or removed dynamically to represent areas of interest in digital images using so called layered architecture that separates image layer from annotation layer. XML files are used to record participants' opinions along with the symbols over some particular images

• 한국기계가공학회지
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• 제18권12호
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• pp.82-90
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• 2019

This analysis demonstrates the effective removal of heat generated from a solar panel's output degradation factor solar cells (the solar panel's output deterioration factor), and solves the problems of oxidation and corrosion in existing metal heat sinks. The heat-dissipating test specimen was prepared using carbon materials; then, its thermal conductivity and its effectiveness in reducing temperatures were studied using heat transfer numerical analysis. As a result, the test specimen of the 30g/㎡ basis weight containing 80% of carbon fiber impregnated with carbon ink showed the highest thermal conductivity 6.96 W/(m K). This is because the surface that directly contacted the solar panel had almost no pores, and the conduction of heat to the panels appeared to be active. In addition, a large surface area was exposed to the atmosphere, which is considered advantageous in heat dissipation. Finally, numerical analysis confirmed the temperature reduction effectiveness of 2.18℃ in a solar panel and 1.08℃ in a solar cell, depending on the application of heat dissipating materials.