• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.942-948
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• 2002

When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and the strength development may be delayed. One of the solution methods to resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerator for freeze protection. In this study we Investigate the effect on the strength development of cement mortar using accelerator for freeze protection with the variable curing condition. As the result of this study, the mortar using accelerator for freeze protection show continuously the strength development in curing condition of -5$^{\circ}C$. And the compressive strength under variable temperature condition was higher than constant temperature condition in same maturity.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.840-847
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• 2003

Recently, the coal-ash production has been increased by increase of consumption of electric power. So it is important to secure a reclaimed land and treatment utility for coal-ash. This is an experimental study to compare and analyze the engineering properties of concrete according to W/C and replacement ratio of bottom ash. For this purpose, the mix proportions of concrete according to W/C(40, 50, 60%) and replacement ratio of bottom ash(0, 10, 20, 35, 50%) were established, and then tested for slump, chloride content, setting time, bleeding content, compressive strength. Also the durability test of concrete with W/E 60% was performed. According to test results, it was found that the bleeding content of concrete decreased as the replacement ratio of bottom ash increased. And the chloride content of concrete using the bottom ash increased as the replacement ratio of bottom ash increased, but it is satisfied with the chloride content of fresh concrete $0.30kg/m^3$ below("concrete standard specification" regulation value). The compressive strength of concrete using the bottom ash was similar to that of BA0 concrete after 28 days of curing and the carbonation depth of concrete was increased according to increase of the replacement ratio of bottom ash.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.15-21
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• 2015

Recently, attempts of replacing some of natural aggregate with mix of low quality aggregate are carried out for stable supply of aggregate. However, low quality aggregate such as recycled aggregate produced during the disposal process of construction wastes and by-product aggregate produced by industrial activities has problem of failing to comply to KS Standards. Therefore, we have compared fundamental properties of concrete by using granite crushed aggregate, recycled aggregate, blast furnace and electric arc furnace slag aggregate for effective utilization of lacking aggregate resources. As the result, slump in case of mixed use of aggregate was increased 0~10% compared to single use. Therefore, it is judged to be economically advantageous as it can expect effects in unit quantity or reduction of SP agent. Compressive strength in case of mixed use of aggregate was increased 0~10% compared to single use as it filled internal crevice of concrete with continuous particle size distribution. Accordingly, if we utilize by satisfying standard particle scope through mix of aggregate with different cause of formation in proper ratio, it was possible to confirm utility of mixed aggregate with demonstration of effects of increases of fluidity and compressive strength of concrete.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.108-117
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• 2016

In this paper, a portal system compatible with MRV regulation was designed to monitoring, reporting and verifying $CO_2$ emission and fuel consumption data from an international ship. A portal system supports monitoring and reporting task of international shipping companies and calculates national greenhouse gas inventory. EU MRV law, MRV discussions of IMO, responses of international shipping companies to ship energy efficiency and greenhouse gas regulation, and greenhouse gas statistics on international shipping were analyzed to drive portal system requirements. For ship energy efficiency and $CO_2$ emitted monitoring, a data collection module was designed based on on-board equipment, energy efficiency measuring device and navigation report. Data transfer module with easy management and minimized usage to transfer ship data to shore was designed. A portal system was designed to convert the collected data into the standard reporting format, perform monitoring, statical analysis, verification and auto report generation, and support national greenhouse gas inventory.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.11a
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• pp.363-369
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• 2002

가정 내에서의 초고속망 이용이 활성화되면서 가정 내에서의 활동은 매우 다양하고 복잡하며 그에 따른 서비스도 여러 가지 형태가 존재한다. 외부 인터넷망과 연동되는 홈 네트워크의 개념이 생기기 전부터 흠 오토메이션, 홈시큐리티 등의 서비스를 제공하기 위한 고립적인 형태의 망과 서비스 제공 시스템이 있었다. 월드 와이드 웹 서비스를 기본으로 한 인터넷의 폭발적인 활성화와 고속 인터넷망의 확산에 따라 가정 내에서 제공되는 서비스를 인터넷과 연계시키려는 시도가 보편화되었고 가정 내에서 사용되는 독립적인 기기들을 인터넷에 연결하여, 외부의 정보를 이용해서 활용하거나, 가전내의 기기들을 외부에서 액세스할 수 있게 되었다. 이렇게 하여 보다 풍부한 서비스를 제공하고, 사용상의 시간적인 제약을 완화할 수 있다. 예들 들어 인터넷상에서 조리법을 전송받아 전자레인지를 작동할 수 있으며, 외부에서 잘못 켜둔 가스밸브를 잠글 수도 있다. 가정 내에서 wrhd되던 이러한 서비스들은 서로 다른 하드웨어와 통신방법을 사용하고 있어, 이러한 서비스를 통합하여 운영, 관리할 수 있도록 하는 흠 서버의 개념이 대두되었다. 외부 인터넷 망과 연계된 흠 오토메이션, 홈 시큐리티등을 제공할 수 있는 기반이 마련되었고, 가정 내에서 독립적으로 제공되던 서비스들을 단일 홈 서버를 통해서 관리하려는 시도가 진행되었다. 그러나 홈 서버는 개발하는 업체의 보유기술에 따라 중심기능은 약간씩 차이를 보이고 있다. 홈 서버 응용 영역은 전문 지식을 소유한 인력과의 연계가 필요하고, 다양한 서비스 영역 행위가 아주 복잡하기 때문에 이들을 연결해 주는 자치 시스템을 필요로 한다. 또한 홈 서버 서비스 영역에서 정보는 각 영역 전문가가 가진 지식의 전달을 필요로 하기 때문에, 지식을 주고받는 멀티 에이전트의 시스템의 활용 영역으로 적당하다. 멀티 에이전트 시스템은 분산된 환경에서 에이전트간에 에이전트 통신 언어를 사용해서 대화를 하기도 하고, 상호 협력하는 에이전트들로 구성된 시스템을 뜻하며 흠 서버처럼 동적이고 고도의 자치성을 요구하는 영역에 적당하다. 멀티 에이전트 플랫폼으로는 FIPA(Foundation for Intelligent Physical Agents)가 제시한 에이전트 표준 플랫폼이 1997년부터 2000년에 이르기까지, 계속적으로 변화, 발전하고 있다. 본 연구는 FIPA에서 제시하는 플랫폼을 기반으로 홈 서버에 정보가전을 제어하는 에이전트를 두고 외부에서 다른 에이전트가 홈 서버에 위치하는 에이전트와의 통신을 통하기 정보가전을 지능적으로 제어하도록 하였다. 정보가전 에이전트는 가정 내 가전제품을 외부에서 제어하기 위한 에이전트이다. 단순한 관리가 아닌 에이전트로 하여금 지능적으로 가전제품 관리를 하게 한다. 정보가전 에이전트는 홈 서버에서 작동하는 에이전트와 PDA에서 작동하는 에이전트로 구성된다. 정보가전 에이전트는 전력량, 수도 사용량 제어와 가전제품 제어 기능과 보안 관련 서비스를 제공한다. 두 에이전트는 FIPA에서 정의된 규격에 맞게 만들어지기 때문에 FIPA명세서를 따르는 다른 에이전트와 자유로운 통신이 가능하다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.430-441
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• 2006

As the various A/V devices and home networks are delivered to users, home networks are changing to an entertainment network. It is expected that the required network bandwidth and the amount of usage of media content in home entertainment networks will be increased. Although the access networks and home networks becoming a high speed network, there remains the problems for QoS-guaranteed media content transfer in home networks. Also, in the home network, there can be network traffic caused by applications like video conferencing, video telephone, and VoIP(voice over IP) as well as inner network traffic of home network. Since media content transfer requires the real-time delivery, it is very important and basic requirement that is to transfer media content to A/V device user wants while keeping the media quality. Even though there are many middleware protocol for home networking, they provide basic device discovery and control or simple functions for QoS-guaranteed media content transfer that are not enough to provide QoS-guaranteed media transfer service that user wants. Thus, in this paper, we propose the technique based on UPnP(universal plug and play) protocol for QoS-guaranteed media content transfer in the home network. The proposed technique is compatible with UPnP and can be used with UPnP as additional functions. In this paper, we utilize VideoLAN application to verify the proposed technique. We add the additional modules that support the proposed technique's function to VideoLAN and we verify the its functions through various test scenarios.

• The Korean Journal of Pesticide Science
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• v.13 no.2
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• pp.70-78
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• 2009

Processing factors of pesticides in milling process of wheat grain, which are consumed and imported at large quantity were examined to establish reasonable MRL of the processed food. Azinphos-methyl, chlorpyrifos, chlorpyrifos-methyl, fenitrothion, malathion, and trichlorfon were selected for the study according to annual usage and the previous detection record in wheat grain. Dipping process for pesticide application was performed in laboratory, while milling process was conducted under pilot plant system. Processing factors were calculated by analyzing residual pesticides on wheat grain and processing products as wheat flour, bran and red dog. Processing factors were 0.05 for azinphos-methyl, 0.06 for chlorpyrifos, 0.05 for chlorpyrifos-methyl, 0.07 for fenitrothion, 0.07 for malathion, 0.06 for trichlorfon, respectively. Recovery test was also performed to establish extraction efficiency of analytical procedure. The recovery value ranged from 93.2% to 98.6% with standard deviation of 0.1-0.9%.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.51-60
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• 2009

This study investigates the fresh state characteristics, strength, chloride ion penetration resistance and freeze-thaw resistance of the suggested high strength-high durability cement concrete pavement. The required workability and air content could be achieved by using an appropriate admixtures. However its dosage should be carefully determined through field trial batches. Compressive strength increased with the increased cement content and, in particular, high cement volume concrete continuously developed strength up to 90 days. No clear relationship, however, existed between flexural strength and cement content. Chloride penetration resistance seemed as a function of curing age rather than the cement content. Freeze-thaw resistance test was conducted using two different coolants, tap water and 4% NaCl solution. When the tap water was used no severe damage was observed up to 300 cycles regardless the air content. Under 4% NaCl solution, specimens of 326kg/$m^3$ cement content showed severe damage with surface scaling. Based on the experimental investigations herein, it is highly recommended that the cement content be greater than 400kg/$m^3$ for strength-high durability cement concrete pavement structures.

• Journal of Korea Water Resources Association
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• v.49 no.8
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• pp.685-692
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• 2016

This study aimed to develop the indicator-based approach to assess water use vulnerability in watersheds and applied to the unit watershed within the Han River watershed. Vulnerability indices were comprised of three sub-components (exposure, sensitivity, adaptive capacity) with respect to water use. The indicators were made up of 16 water use indicators. Then we estimated vulnerability indices using the Technique for Order of Preference by Similarity to Ideal Solution approach (TOPSIS). We collected environmental and socio-economic data from national statistics database, and used them for simulated results by the Soil and Water Assessment Tool (SWAT) model. For estimating the weighted values for each indicator, expert surveys for subjective weight and data-based Shannon's entropy method for objective weight were utilized. With comparing the vulnerability ranks and analyzing rank correlation between two methods, we evaluated the vulnerabilities for the Han River watershed. For water use, vulnerable watersheds showed high water use and the water leakage ratio. The indices from both weighting methods showed similar spatial distribution in general. Such results suggests that the approach to consider different weighting methods would be important for reliably assessing the water use vulnerability in watersheds.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.30-35
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• 1999

A simple, rapid, efficient method is for extraction of 13 synthetic water-soluble food colours (Tartrazine, Amarnth, Indigo carmine, New coccine, Sunset yellow FCF, Allura red AC, Eosine, Fast Green FCF, Brilliant Blue FCF, Erythrosine, Acid red, phloxine, Rose Bengal) by polyamide resin and for their quantitative by high performance liquid chromatography (HPLC). Colours (coal-tar dyes) were extracted with polyamide resin and then determinated by HPLC. The HPLC conditions using a reverse phase partition type column $(Nova-pak\;C_{18})$, photodiode array (PDA) detector and 1% Ammonium acetate / 60% acetonitrile in water as eluent, were acceptable for various kinds of colorants. By the use of the proposed method, a survey of coal-tar dyes was carried out on 20 samples and that were detected $4.76{\sim}133.47\;ppm$.