• 신재생에너지
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• 제8권4호
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• pp.21-29
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• 2012

The extensible supply of New & Renewable energy resources desperately needs to counter the high dependence on imported energy, recent high oil prices and the Climate Change Conference, and the government has operated the 'Renewable Portfolio Standard' (RPS) as one of the renewable energy policy from 2012. By analyzing the operation case of combined heat and power plant using the woodchip biomass, we drew the price of wood chip fuel, plant capacity factor, electricity selling price, heat selling price and LCOE value. After analyzing the economic feasibility of 3MWe combined heat and power plant based on the operating performance, the minimum of economic feasibility has appeared to be secured according to the internal rate of return (IRR) is 6.34% and the net present value (NPV) is 3.6 billion won as of 20 years life time after installation, and after analyzing the cases of the economic feasibility of the price of wood chip, plant capacity factor, electricity and heat selling price are changed, the economic feasibility is valuable when the price of wood chip is over 64,000 won/ton, NPV is minus, and the capacity factor is above 46.9%, the electricity selling price is 116 won/kWh and the heat selling price is above 75,600 won/Gcal. When going over the new installation hereafter, we need the detailed review of the woodchip storage and woodchip feeding system rather than the steam-turbine and boiler which have been inspected many times, the reason why is it's hard to secure the suitable quality (constant size) of woodchip by the lack of understanding about it as a fuel because of the domestic poor condition and the calorific value of woodchip is seriously volatile compared with other fuels.

• 한국기계가공학회지
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• 제18권9호
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• pp.29-35
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• 2019

The structure of the machinery industry due to the 4th industrial revolution is changing from precision and durability to intelligent and smart machinery through sensing and interconnection(IoT). There is a growing need for research on prognostics and health management(PHM) that can prevent abnormalities in processing machines and accurately predict and diagnose conditions. PHM is a technology that monitors the condition of a mechanical system, diagnoses signs of failure, and predicts the remaining life of the object. In this study, the vibration generated during machining is measured and a classification algorithm for normal and fault signals is developed. Arbitrary fault signal is collected by changing the conditions of un stable supply cutting oil and fixing jig. The signal processing is performed to apply the measured signal to the learning model. The sampling rate is changed for high speed operation and performed machine learning using raw signal without FFT. The fault classification algorithm for 1D convolution neural network composed of 2 convolution layers is developed.

• 한국식생활문화학회지
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• 제21권2호
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• pp.142-153
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• 2006

This study was planned to investigate the current using status of agricultural products in school food service both produced in Korea and imported from other countries and the dieticians' perception on using those. A total of 723 dieticians of 442 elementary schools and 381 middle high schools were surveyed in July, 2003 to perform the purposes of the study. A high using rate (93.4%) for Korean agricultural products was investigated. As for meat such as pork and chicken except beef and eggs, the using rate of Korean agricultural products was high. Almost 100% of vegetables and fruits, except tropical fruits such as banana, kiwi, orange and pineapple supplied for school food service were also Korean products. As for nuts and edible oil, the rate of using for Korean agricultural products was comparatively lower than those of other food items due to the price gap. Most dieticians rated the quality of the products produced in Korea higher than that of the imported products in the aspects of their freshness, taste, and safety. But they found no difference in the package condition of the products produced in Korea and of those imported from other countries. This result suggests that the package system should be improved for the agricultural products produced in Korea.

• 환경위생공학
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• 제7권2호
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• pp.1-10
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• 1992

Since 1960's along with industrialization and urbanization, economic growth has been . achieved, however, at the same time, environmental condition has been seriously deteriorated. . Currently, volume of wastewater has been increasing at annual rate of 7% in sewage and 20% in industrial wastewater. However, the nation's sewage treatment serves only 33% of the municipal wastewater as of 1991. Major portion of air pollutants comes from combustion of oil and coal which comprise 81% of total energy use and emission gases from motor vehicles increasing at an accelerated rate. It is known that Korea generates the highest amount of waste per capta. Nevertheless, it is not sufficient to reduce the volume of waste by means of resources recovery and recycling. Recognizing the importance of global environmental problems such as ozone layer depletion, global warming and acid rain, international society has been making various efforts since the 1972 Stockholm conference. In particular, it is expected that the Rio conference which has adopted the Rio declaration and Agenda 21 will form a crucial turning point of the emerging new world order after the Cold War confrontation. To cope with such issues as domestic pollution and global environmental problems, the fundamental national policy aims at harmonizing "environmental protection and sustainable development". The Ministry of Environment has recently set up a mid-term comprehensive plan which includes annual targets for environmental protection. According to the government plan, gradual improvement of various environmental conditions and specific measures to achieve them is planned in time frame. Additional sewage treatment plants will be constructed in urban areas with the target to treat 65% of the nation's municipal sewage by 1996. Supply of clean fuels such as LNG will also be expanded starting from large cities as a cleaner substitute energy for coal and oil. In parallel with expansion of LNG, emphasis will be placed on installation of stack monitoring system. Due to the relatively limited land, government's basic policy for solid waste treatment is to develop large scale landfill facilities rather than small sized ones. Thirty three regional areas have been designated for the purpose of waste management. For each of these regions, big scale landfill site is going to be developed. To increase the rate of waste recycling the government is planning to reinforce separate collection system and to provide industries with economic incentives. As a part of meeting the changing situation on global environmental problems after UNCED, and accommodation regulatory measures stipulated in the global environmental conventions and protocols, national policy will try to alter industrial and economic structure so as to mitigate the increasing trends of energy consumption, by encouraging energy conservation and efficiency. In this regard, more attention will be given to the policy on the development of the cleaner technology. Ultimately, these policies and programs will contribute greatly to improving the current state of national public health.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.101-101
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• 2010

Anaerobic digestion(AD) is the most promising method for treating and recycling of different organic wastes, such as organic fraction of municipal solid waste, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. organic materials are decomposed by anaerobic forming bacteria and fina1ly converted to excellent fertilizer and biogas which is a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to produce renewable energy and to reduce $CO_2$ and other green-house gas(GHG) emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. Currently some 80% of the world's overall energy supply of about 400 EJ per year in derived from fossil fuels. Nevertheless roughly 10~15% of this demand is covered by biomass resources, making biomass by far the most important renewable energy source used to date. The representative biofuels produced from the biomass are bioethanol, biodiesel and biogas, and currently biogas plays a smaller than other biofuels but steadily growing role. Traditionally anaerobic digestion applied for different biowaste e.g. sewage sludge, manure, other organic wastes treatment and stabilization, biogas has become a well established energy resource. However, the biowaste are fairly limited in respect to the production and utilization as renewable source, but the plant biomass, the so called "energy crops" are used for more biogas production in EU countries and the investigation on the biomethane potential of different crops and plant materials have been carried out. In Korea, with steadily increasing oil prices and improved environmental regulations, since 2005 anaerobic digestion was again stimulated, especially on the biogasification of different biowastes and agro-industrial biomass including "energy crops". This study have been carried out to investigate anaerobic biodegradability by the biochemical methane potential(BMP) test of animal manures, different forage crops i.e. "energy crops", plant and industrial organic wastes in the condition of thermophilic temperature, The biodegradability of animal manure were 63.2% and 58.2% with $315m^3CH_4/tonVS$ of cattle slurry and $370m^3CH_4/tonVS$ of pig slurry in ultimate methane yields. Those of winter forage crops were the range 75% to 87% with ultimate methane yield of $378m^3CH_4/tonVS$ to $450m^3CH_4/tonVS$ and those of summer forage crops were the range 81% to 85% with ultimate methane yield of $392m^3CH_4/tonVS$ to $415m^3CH_4/tonVS$. The forge crops as "energy crops" could be used as good renewable energy source to increase methane production and to improve biodegradability in co-digestion with animal manure or only energy crop digestion.

• Asia pacific journal of information systems
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• 제24권4호
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• pp.443-472
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• 2014

To survive in the global competitive environment, enterprise should be able to solve various problems and find the optimal solution effectively. The big-data is being perceived as a tool for solving enterprise problems effectively and improve competitiveness with its' various problem solving and advanced predictive capabilities. Due to its remarkable performance, the implementation of big data systems has been increased through many enterprises around the world. Currently the big-data is called the 'crude oil' of the 21st century and is expected to provide competitive superiority. The reason why the big data is in the limelight is because while the conventional IT technology has been falling behind much in its possibility level, the big data has gone beyond the technological possibility and has the advantage of being utilized to create new values such as business optimization and new business creation through analysis of big data. Since the big data has been introduced too hastily without considering the strategic value deduction and achievement obtained through the big data, however, there are difficulties in the strategic value deduction and data utilization that can be gained through big data. According to the survey result of 1,800 IT professionals from 18 countries world wide, the percentage of the corporation where the big data is being utilized well was only 28%, and many of them responded that they are having difficulties in strategic value deduction and operation through big data. The strategic value should be deducted and environment phases like corporate internal and external related regulations and systems should be considered in order to introduce big data, but these factors were not well being reflected. The cause of the failure turned out to be that the big data was introduced by way of the IT trend and surrounding environment, but it was introduced hastily in the situation where the introduction condition was not well arranged. The strategic value which can be obtained through big data should be clearly comprehended and systematic environment analysis is very important about applicability in order to introduce successful big data, but since the corporations are considering only partial achievements and technological phases that can be obtained through big data, the successful introduction is not being made. Previous study shows that most of big data researches are focused on big data concept, cases, and practical suggestions without empirical study. The purpose of this study is provide the theoretically and practically useful implementation framework and strategies of big data systems with conducting comprehensive literature review, finding influencing factors for successful big data systems implementation, and analysing empirical models. To do this, the elements which can affect the introduction intention of big data were deducted by reviewing the information system's successful factors, strategic value perception factors, considering factors for the information system introduction environment and big data related literature in order to comprehend the effect factors when the corporations introduce big data and structured questionnaire was developed. After that, the questionnaire and the statistical analysis were performed with the people in charge of the big data inside the corporations as objects. According to the statistical analysis, it was shown that the strategic value perception factor and the inside-industry environmental factors affected positively the introduction intention of big data. The theoretical, practical and political implications deducted from the study result is as follows. The frist theoretical implication is that this study has proposed theoretically effect factors which affect the introduction intention of big data by reviewing the strategic value perception and environmental factors and big data related precedent studies and proposed the variables and measurement items which were analyzed empirically and verified. This study has meaning in that it has measured the influence of each variable on the introduction intention by verifying the relationship between the independent variables and the dependent variables through structural equation model. Second, this study has defined the independent variable(strategic value perception, environment), dependent variable(introduction intention) and regulatory variable(type of business and corporate size) about big data introduction intention and has arranged theoretical base in studying big data related field empirically afterwards by developing measurement items which has obtained credibility and validity. Third, by verifying the strategic value perception factors and the significance about environmental factors proposed in the conventional precedent studies, this study will be able to give aid to the afterwards empirical study about effect factors on big data introduction. The operational implications are as follows. First, this study has arranged the empirical study base about big data field by investigating the cause and effect relationship about the influence of the strategic value perception factor and environmental factor on the introduction intention and proposing the measurement items which has obtained the justice, credibility and validity etc. Second, this study has proposed the study result that the strategic value perception factor affects positively the big data introduction intention and it has meaning in that the importance of the strategic value perception has been presented. Third, the study has proposed that the corporation which introduces big data should consider the big data introduction through precise analysis about industry's internal environment. Fourth, this study has proposed the point that the size and type of business of the corresponding corporation should be considered in introducing the big data by presenting the difference of the effect factors of big data introduction depending on the size and type of business of the corporation. The political implications are as follows. First, variety of utilization of big data is needed. The strategic value that big data has can be accessed in various ways in the product, service field, productivity field, decision making field etc and can be utilized in all the business fields based on that, but the parts that main domestic corporations are considering are limited to some parts of the products and service fields. Accordingly, in introducing big data, reviewing the phase about utilization in detail and design the big data system in a form which can maximize the utilization rate will be necessary. Second, the study is proposing the burden of the cost of the system introduction, difficulty in utilization in the system and lack of credibility in the supply corporations etc in the big data introduction phase by corporations. Since the world IT corporations are predominating the big data market, the big data introduction of domestic corporations can not but to be dependent on the foreign corporations. When considering that fact, that our country does not have global IT corporations even though it is world powerful IT country, the big data can be thought to be the chance to rear world level corporations. Accordingly, the government shall need to rear star corporations through active political support. Third, the corporations' internal and external professional manpower for the big data introduction and operation lacks. Big data is a system where how valuable data can be deducted utilizing data is more important than the system construction itself. For this, talent who are equipped with academic knowledge and experience in various fields like IT, statistics, strategy and management etc and manpower training should be implemented through systematic education for these talents. This study has arranged theoretical base for empirical studies about big data related fields by comprehending the main variables which affect the big data introduction intention and verifying them and is expected to be able to propose useful guidelines for the corporations and policy developers who are considering big data implementationby analyzing empirically that theoretical base.