• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.4 s.235
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• pp.453-459
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• 2005

In this paper, we are proposing a robust tool which is capable of measuring the size and elemental composition of submicron particles from twenty to several hundreds nanometers at the same time, i.e., named Single Particle Mass Spectrometer (SPMS). The home-made SPMS employs a laser ablation/multi-photon ionization method to tear a nanoparticle into the constituent elemental ions. One thing different from the conventional Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) is the power of the ionization laser. Much strong laser used in this work makes it possible to generate elemental ions rather than molecular ions from a nanoparticle. Also the use of high power laser may guarantee a complete ionization of a particle, which was confirmed by the existence of multiple charged ions. If a particle is evaporated/ionized completely and detected through electric field-free TOF tube without any loss, we can extract the original particle volume from the measured total ion numbers. Collecting a number of particles mass spectra, we get a database of size and elemental composition of nanoparticles, with which we may take a took into any kinds of chemical reaction occurring at nanoscale. Several issues related to size estimation by SPMS will be discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1311-1314
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• 2012

최근에는 LED 조명으로 인해 조명 제어의 유연성이 높아짐에 따라 가정이나 사무공간에서 해당 공간의 목표 조도를 설정하고 현재 내부조도의 상황에 따라 자동으로 조명을 디밍하는 형태로 연구가 이루어지고 있다. 그러나 이러한 제어방식이 현재 주택용 요금제도로 운영 중인 고정요금제에서는 에너지 비용을 감소시키나, 스마트그리드에서 운영될 RTP(Real Time Pricing)에서는 요금 단계에 따라 오히려 에너지 비용이 증가될 수 있다. 이에 본 논문은 실시간 요금 단계에 따라 LED 조명의 목표 조도를 가변적으로 변화시켜 조명 에너지 비용을 최소화하고 사용자의 작업에 적합한 상황별 조도를 자동으로 제어하여 작업자에게 편리함을 제공하고자 한다. 이때 요금 단계에 따른 상황별 최저 및 최고 조도기준은 KSA 3011 및 IES를 참조하며, 최소한의 조명 에너지 사용을 위해 외부 광량을 최대한 활용하여 현재의 시간에 따라 블라인드의 Open/Close를 자동으로 서비스한다. 사용자의 상황은 PIR, Electric Powermeter, Piezoelectric 센서로부터 사용자의 위치, 가전기기 사용 유무, 착석 여부 등을 파악하고, RTP 요금에 따라 하루동안의 조명에 사용된 전력요금을 시뮬레이션한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.1
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• pp.97-115
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• 2022

Smart power grid is a user friendly system that transforms the traditional electric grid to the one that operates in a co-operative and reliable manner. Demand Response (DR) is one of the important components of the smart grid. The DR programs enable the end user participation by which they can communicate with the electricity service provider and shape their daily energy consumption patterns and reduce their consumption costs. The increasing demands of electricity owing to growing population stresses the need for optimal usage of electricity and also to look out alternative and cheap renewable sources of electricity. The solar and wind energy are the promising sources of alternative energy at present because of renewable nature and low cost implementation. The proposed work models a smart home with renewable energy units. The random nature of the renewable sources like wind and solar energy brings an uncertainty to the model developed. A stochastic dual descent optimization method is used to bring optimality to the developed model. The proposed work is validated using the simulation results. From the results it is concluded that proposed work brings a balanced usage of the grid power and the renewable energy units. The work also optimizes the daily consumption pattern thereby reducing the consumption cost for the end users of electricity.

• Korea Trade Review
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• v.45 no.4
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• pp.65-81
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• 2020

Under New Climate Regime, countries are trying to enhance environmental regulations to meet international standards. This study is designed to examine the relationship between the relative level of environmental regulation of the importing countries and the export performance at the industrial level. Panel data from 2009 to 2018 was established for 12 top export industries and empirical analysis was conducted. For the analysis method, panel OLS, Hausman-Taylor, and panel GLS were used based on the results of the Hausman verification. The dependent variable is the export performance of each industry. As the independent variables, the relative level of environmental regulation, GDP per capita of the importing country, exchange rate, FTA agreement, and physical distance from the importing country were used. Results show that the relative level of environmental regulation has a negative effect on export performance of semiconductors, displays, special machines, general machines, electric appliances, and home appliances. On the other hand, there are no relationship between the relative level of environmental regulation of the importing country and export performance of automobile, petroleum refining, petrochemical, shipbuilding, and communication equipment industries.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.583-597
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• 2014

Fire caused by heater has various causes as many as the types of heater. also, lots of damage of human life and property loss are caused, since annually continuous fire accident by heater in traditional market is frequently occurring. There are not many cases of fire due to heater in most of residential facilities such as general house, apartments, etc., because they are supplied with heating boiler, however the restaurant, store and office of the market, sports center, factory, workplace, etc. still use heater, e.g. oilstove, electric heater, etc., so that they are exposed to fire hazard. Also, when investigating the number of fire due to heater, it was analyzed to occur in order of home boiler, charcoal stove, oilstove, gas heater/stove, electric stove/heater, the number of fire per human life damage was analyzed in order of gas heater/stove, oil heater/stove, electric heater/stove, briquette/coal heater. Also, gas and oil related heater were analyzed to have low frequency, however, with high fire intensity. Therefore, this research aimed at considering more scientific fire inspection and identification approach by reenacting and reviewing fire outbreak possibility caused by combustibles' contact and conductivity under the normal condition and abnormal condition in respect of ignition hazard, i.e. minimum ignition temperature, carbonization degree and heat flux along with it, due to oilstove and electric stove, which are still frequently used in public use facility, traditional market, and, of which actual fire occurrence is the most frequent. As the result of reenact test, ignition hazard appeared very small, as long as enough heat storage condition is not made in both test objects(oilstove/electric stove), however carbonization condition was analyzed to be proceeded per each part respectively. Eventually, transition to fire is the ignition due to heat storage, so that it was analyzed to ignite when minimum heat storage temperature condition of fire place is over $500^{\circ}C$. Particularly, in case of quartz pipe, the heating element of electric stove, it is rapidly heated over the temperature of $600^{\circ}C$ within the shortest time(10sec), so that the heat flux of this appears 6.26kW/m2, which was analyzed to result in damage of thermal PVC cable and second-degree burn in human body. Also, the researcher recognized that the temperature change along with Geometric View Factor and Fire Load, which display decrease of heat, are also important variables to be considered, along with distance change besides temperature condition. Therefore, the researcher considers that a manual of careful fire inspection and identification on this is necessary, also, expects that scientific and rational efforts of this research can contribute to establish manual composition and theoretical basis on henceforth fire inspection and identification.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.19-26
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• 2010

A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be coped with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. The thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, thermal management system of PEMFC stack is modeled to understand the dynamic response during load change. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. The different operating strategy is applied for each cooling circuit considering the duty of those two circuits. Even though the capacity of PEMFC system (1kW) is enough to supply hot domestic water for residence, heat-up of reservior takes some hours. Therefore, in this study, time schedule of the simulation reflects the heat-up process. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.869-874
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• 2004

Digital TV broadcasting's resolution or tone quality is very excellent than analog broadcasting and has many advantages including various multimedia functions such as home shopping, home banking, internet search, telecommuting, VOD, etc. In this study, it is essential to analyze the regional electromagnetic environment before Digital TV broadcasting, and therefore we analyzed Busan area's limitation using ETRI propagation model. For maintaining high-quality Digital TV signals, we measure electric field intensity wide and far in Busan including mountains area and high-rise buildings. Generally, it has lower value by a standard ETRI propagation model than simulated value about standard model, but distribution pattern are similar with it. Compared theoretical values with the measured results, they have similar values for flat area but very different values for crowded city area and mountains area So we conclude that ETRI propagation model and theoretical model are not suitable for Busan in a free space.

• Journal of Internet Computing and Services
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• v.14 no.6
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• pp.33-39
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• 2013

When the eldery with limited mobility and disabled use a wheelchairs to move, it can cause decreased exercise ability like decline muscular strength in upper limb and lower extremities. The disabled people suffers with spinal cord injuries or post stroke hemiplegia are easily exposed to secondary problems due to limited mobility. In this paper, We designed intelligent wheelchair robot system for upper limb and lower extremities exercise/rehabilitation considering the characteristics of these severely disabled person. The system consists of an electric wheelchair, biometrics module for Identification characteristics of users, upper limb and lower extremities rehabilitation. In this paper, describes the design and configurations and of developed robot. Also, In order to verify the system function, conduct performance evaluation targeting non-disabled about risk context analysis with biomedical signal change and upper limb and lower extremities rehabilitation over wheelchair robot move. Consequently, it indicate sufficient tracking performance for rehabilitation as at about 86.7% average accuracy for risk context analysis and upper limb angle of 2.5 and lower extremities angle of 2.3 degrees maximum error range of joint angle.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.4
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• pp.407-413
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• 2011

This paper presents an electrical power monitoring system for home energy management and an automatic appliance-identification algorithm based on the electricity-usage patterns collected during the monitoring tests. This paper also discusses the results of the field tests of which the proposed system was voluntarily deployed at 13 homes. The proposed monitoring system periodically measures the amount of power consumption of each appliance with a pre-specified time interval and effectively displays the essential information provided by the monitored data which is required users to know in order to save power consumption. Regarding the field tests of the monitoring system, the households responded that the system was useful in saving electricity and especially the electricity-usage patterns per appliances. They also considered that the predicted amount of the monthly power consumption was effective. The proposed appliance-identification algorithm uses 4 patterns: Zero-Crossing Rate(ZC), Variation of On State(VO), Slope of On State(SO) and Duty Cycle(DC), which are applied over the 2 hour interval with 25% of it on state, and it yielded 82.1% of success rate in identifying 5 kinds of appliances: refrigerator, TV, electric rice-cooker, kimchi-refrigerator and washing machine.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.160-163
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• 1998

In this study, the compostable household wastes from a house were composted in a home composter without adding any bulking agent and microorganisms. Every day wastes of 1kg were added to the composter during the experimental period. The following results were obtained : 1. Each component of the compostable household wastes generated every day showed very difference. 2. While composting proceeded at room temperature by suppling 1,1322 l air per hour, the composting material maintained the water content of 74.36 ${\sim}$ 85.14%, whereas while composting proceeded at $45^{\circ}C$ by suppling 427 l air per hour, the compost had optimal water content. The electric power of 132kwh a month was required by operating the composting unit at $45^{\circ}C$. 3. During 20 day, decomposition of 28% at room temperature and 44% at $45^{\circ}C$ were obtained respectively. 4. The accumulation of inorganic compound contents were not shown during the composting period, However, the content of salt and Cd was very high. Therefore, using the compost for agriculture has to be careful. 5. The biofilter removed the odorous substants efficiently at the room temperature due to increasing surface loading.