• Title/Summary/Keyword: Electricity Sales

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Development of Forecasting Model for the Initial Sale of Apartment Using Data Mining: The Case of Unsold Apartment Complex in Wirye New Town (데이터 마이닝을 이용한 아파트 초기계약 예측모형 개발: 위례 신도시 미분양 아파트 단지를 사례로)

  • Kim, Ji Young;Lee, Sang-Kyeong
    • Journal of Digital Convergence
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    • v.16 no.12
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    • pp.217-229
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    • 2018
  • This paper aims at applying the data mining such as decision tree, neural network, and logistic regression to an unsold apartment complex in Wirye new town and developing the model forecasting the result of initial sale contract by house unit. Raw data are divided into training data and test data. The order of predictability in training data is neural network, decision tree, and logistic regression. On the contrary, the results of test data show that logistic regression is the best model. This means that logistic regression has more data adaptability than neural network which is developed as the model optimized for training data. Determinants of initial sale are the location of floor, direction, the location of unit, the proximity of electricity and generator room, subscriber's residential region and the type of subscription. This suggests that using two models together is more effective in exploring determinants of initial sales. This paper contributes to the development of convergence field by expanding the scope of data mining.

Greenhouse Gas Emissions from Building Sector based on National Building Energy Database (국가 건물에너지 통합DB 기반 건물부문 온실가스 배출현황)

  • Ji, Chang-Yoon;Choi, Min-Seok;Gwon, Oh-In;Jung, Ha-Rim;Shin, Sung-Eun
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.4
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    • pp.143-152
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    • 2020
  • This study analyzes in detail greenhouse gas emissions in building sector. To this end, this study used data on building characteristics (including building type, region, and construction year) and monthly energy consumptions (including electricity, city gas, and district heat) for all buildings from 2015 to 2018. These data were collected from the National Building Energy Database and the energy consumptions were converted into greenhouse gas (GHG) emissions. The total amount of GHG emissions from the building sector has increased steadily from 2015 (118.1MtCO2eq.) to 2018 (132.6MtCO2eq.). On the other hand, the more recently constructed buildings had lower GHG intensities. This result shows that strengthening building design criteria was effective on the reduction of GHG emissions in buildings, and that the increased buildings contributed to increasing GHG emissions of the building sector. In addition, sales facilities are thought to have the largest reduction potential as they had the highest amount of GHG emissions and GHG intensity. This study is expected to help establish new policies for GHG reduction in building sector as well as to evaluate the effects of existing policies.

Effect of the Reactive Power Compensation System on Performance Enhancement in a 900 MW Combined Cycle Power Plant (무효전력보상장치 설치가 900 MW 복합화력발전소의 성능향상에 미치는 효과)

  • Lee, Young Ok;Yoo, Hoseon
    • Plant Journal
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    • v.17 no.2
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    • pp.48-53
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    • 2021
  • In the case of a 900 MW combined cycle power plant, most of the load on the site is a rotating device and is operated at a low power factor, and the power factor decrease increases the reactive power, which causes the efficiency of the device to be consumed and unnecessary unnecessary power consumption. This study intends to present the results by installing and operating a reactive power compensation device that absorbs and removes reactive power, which is a solution to this problem, on a 6.9 kV on-board bus. As a result of application of this system, first, it was confirmed that the power factor of the rotating machine was improved to 0.22 and the load power in the house was reduced by 1.4%, and the thermal efficiency of the generator was increased by 0.1% and the power generation power by 810 kW. Next, it was confirmed that the cost of construction and operation can be reduced in the future due to economic feasibility, with a decrease of 200 million won/year in electricity loss compared to 1.5 billion won in investment, an increase of 1 billion won/year in sales, and a one-year capital recovery period.

Process Simulation and Economic Feasibility of Upgraded Biooil Production Plant from Sawdust (톱밥으로부터 생산되는 개질 바이오오일 생산공장의 공정모사 및 경제성 분석)

  • Oh, Chang-Ho;Lim, Young-Il
    • Korean Chemical Engineering Research
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    • v.56 no.4
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    • pp.496-523
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    • 2018
  • The objective of this study is to evaluate the economic feasibility of two fast pyrolysis and biooil upgrading (FPBU) plants including feed drying, fast pyrolysis by fluidized-bed, biooil recovery, hydro-processing for biooil upgrading, electricity generation, and wastewater treatment. The two FPBU plants are Case 1 of an FPBU plant with steam methane reforming (SMR) for $H_2$ generation (FPBU-HG, 20% yield), and Case 2 of an FPBU with external $H_2$ supply (FPBUEH, 25% yield). The process flow diagrams (PFDs) for the two plants were constructed, and the mass and energy balances were calculated, using a commercial process simulator (ASPEN Plus). A four-level economic potential approach (4-level EP) was used for techno-economic analysis (TEA) under the assumption of sawdust 100 t//d containing 40% water, 30% equity, capital expenditure equal to the equity, $H_2$ price of $1050/ton, and hydrocarbon yield from dried sawdust equal to 20 and 25 % for Case 1 and 2, respectively. TCI (total capital investment), TPC (total production cost), ASR (annual sales revenue), and MFSP (minimum fuel selling price) of Case 1 were $22.2 million, $3.98 million/yr, $4.64 million/yr, and $1.56/l, respectively. Those of Case 2 were $16.1 million, $5.20 million/yr, $5.55 million/yr, and $1.18/l, respectively. Both ROI (return on investment) and PBP (payback period) of Case 1(FPBU-HG) and Case 2(FPBU-EH) were the almost same. If the plant capacity increases into 1,500 t/d for Case 1 and Case 2, ROI would be improved into 15%/yr.

Practical Design of an Artificial Light-Used Plant Factory for Common Ice Plant (Mesembryanthemum crystallinum L.) (인공광 이용형 Common Ice Plant 식물공장의 실용적 설계)

  • Cha, Mi-Kyung;Kim, Ju-Sung;Shin, Jong Hwa;Son, Jung Eek;Cho, Young Yeol
    • Journal of Bio-Environment Control
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    • v.23 no.4
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    • pp.371-375
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    • 2014
  • This study was carried out to get the basic data to practically design an artificial light-used plant factory system for common ice plant (Mesembryanthemum crystallinum L.) cultivation. The adequate range of light intensity was $120-200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and the carbon fixed rates was $0.84nmolCO_2{\cdot}cm^{-2}{\cdot}s^{-1}$. When the planting density, light intensity, and yield were $0.0225m^2$ ($15{\times}15cm$), $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and 1,000 plants per day, the total number of the plants, cultivated area, and total light intensities were estimated as 25,000 plants, $563m^2$, and $140,625{\mu}mol{\cdot}s^{-1}$, respectively. About 153.2kW with 2,785 fluorescent lights (FL) needed for the electric power and the electricity charges was 2.46 million won for one month. At a harvest rate of 1,000 plants per day in closed-type plant factory, the light installation cost, total installation cost, and total production cost were 27.85, 83.56, and 100.27 million won, respectively. The production cost per plant including labor cost was calculated as 370 won, providing that the cultivation period was 25 days and marketable ratio was 80%. Considering the annual total expenses, incomes, and depreciation cost, the sales cost per plant could be estimated around 970 won or higher.

Economic Impact Analysis of Hydrogen Energy Deployment Applying Dynamic CGE Model (동태 CGE 모형을 활용한 수소에너지 보급의 경제적 영향 추정)

  • Bae, Jeong-Hwan;Cho, Gyeong-Lyeob
    • Environmental and Resource Economics Review
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    • v.16 no.2
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    • pp.275-311
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    • 2007
  • Hydrogen energy is emphasized as a substitutable energy of carbon-based energy system in the future, since it is non-depletable and clean energy. Long term vision of Korean government on the national energy system is to promote hydrogen energy by 15% of final energy demand until 2040. This study analyzes economic impacts of hydrogen energy development employing a dynamic CGE model for Korea. Frontier technology such as hydrogen energy is featured as slow diffusion at the initial stage due to the learning effect and energy complementarity. Without government intervention, hydrogen energy would be produced upto 6.5% of final energy demand until 2040. However, if government subsidizes sales price of hydrogen energy by 10%, 20%, and 30%, share of hydrogen energy would increase 9.2%, 15.2%, and 37.7% of final energy demand. This result shows that the slow diffusion problem of hydrogen energy as frontier technology could be figured out by market incentive policy. On the other hand, production levels of transportation sector would increase while growth rate of oil and electricity sectors would decline. Household consumption would be affected negatively since increase of consumption due to the price decrease would be overwhelmed by income reduction owing to the increase of tax. Overall, GDP would not decrease or increase significantly since total production, investment, and export would increase even if household consumption declines.

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Economic Analysis on a PV System in an Apartment Complex (공동주택 태양광발전 시스템의 경제성 평가)

  • Kim, Jin-Hyung
    • Journal of Climate Change Research
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    • v.1 no.2
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    • pp.163-177
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    • 2010
  • This study analyzes the economies of photovoltaic systems in an apartment complex of 1,185 households, in cases of feed-in tariff and subsidy for solar home program of the government. When including the revenue only from electricity sales, NPVs of subsidy and that of feed-in tariff are -560 million KRW and -87 million KRW respectively. With the avoided social cost included without the revenues from CERs, NPVs of subsidy and feed-in tariff are -556 million KRW and -84 million KRW respectively. With the revenues from CERs, NPV of subsidy is -526 million KRW and NPV of feed-in tariff is -54 million KRW. As results of sensitivity analysis based on the changes in capital costs and discount rates, while all scenarios with subsidy including the revenues from CERs are not commercially viable, all scenarios with feed-in tariff exclusive of the revenues from CERs are commercially viable when discount rate is less than 7.2% or capital cost is less than 6,840 thousand KRW/kW. In the cases that include the avoided social cost, while all scenarios with subsidy including the avoided social cost as well as the revenues from CERs are not commercially viable, all scenarios with feed-in tariff are commercially viable without the revenues from CERs when discount rate is less than 7.2% or capital cost is less than 6,856 thousand KRW/KW. The results indicate that the changes in discount rates do not influence the revenues from CERs, but the revenues from electricity sale. Considering that the number of apartment complex and the positive environmental and social benefits from PV system, government needs to promote its diffusion.

A Contemplation on Measures to Advance Logistics Centers (물류센터 선진화를 위한 발전 방안에 대한 소고)

  • Sun, Il-Suck;Lee, Won-Dong
    • Journal of Distribution Science
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    • v.9 no.1
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    • pp.17-27
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    • 2011
  • As the world becomes more globalized, business competition becomes fiercer, while consumers' needs for less expensive quality products are on the increase. Business operations make an effort to secure a competitive edge in costs and services, and the logistics industry, that is, the industry operating the storing and transporting of goods, once thought to be an expense, begins to be considered as the third cash cow, a source of new income. Logistics centers are central to storage, loading and unloading of deliveries, packaging operations, and dispensing goods' information. As hubs for various deliveries, they also serve as a core infrastructure to smoothly coordinate manufacturing and selling, using varied information and operation systems. Logistics centers are increasingly on the rise as centers of business supply activities, growing beyond their previous role of primarily storing goods. They are no longer just facilities; they have become logistics strongholds that encompass various features from demand forecast to the regulation of supply, manufacturing, and sales by realizing SCM, taking into account marketability and the operation of service and products. However, despite these changes in logistics operations, some centers have been unable to shed their past roles as warehouses. For the continuous development of logistics centers, various measures would be needed, including a revision of current supporting policies, formulating effective management plans, and establishing systematic standards for founding, managing, and controlling logistics centers. To this end, the research explored previous studies on the use and effectiveness of logistics centers. From a theoretical perspective, an evaluation of the overall introduction, purposes, and transitions in the use of logistics centers found issues to ponder and suggested measures to promote and further advance logistics centers. First, a fact-finding survey to establish demand forecast and standardization is needed. As logistics newspapers predicted that after 2012 supply would exceed demand, causing rents to fall, the business environment for logistics centers has faltered. However, since there is a shortage of fact-finding surveys regarding actual demand for domestic logistic centers, it is hard to predict what the future holds for this industry. Accordingly, the first priority should be to get to the essence of the current market situation by conducting accurate domestic and international fact-finding surveys. Based on those, management and evaluation indicators should be developed to build the foundation for the consistent advancement of logistics centers. Second, many policies for logistics centers should be revised or developed. Above all, a guideline for fair trade between a shipper and a commercial logistics center should be enacted. Since there are no standards for fair trade between them, rampant unfair trades according to market practices have brought chaos to market orders, and now the logistics industry is confronting its own difficulties. Therefore, unfair trade cases that currently plague logistics centers should be gathered by the industry and fair trade guidelines should be established and implemented. In addition, restrictive employment regulations for foreign workers should be eased, and logistics centers should be charged industry rates for the use of electricity. Third, various measures should be taken to improve the management environment. First, we need to find out how to activate value-added logistics. Because the traditional purpose of logistics centers was storage and loading/unloading of goods, their profitability had a limit, and the need arose to find a new angle to create a value added service. Logistic centers have been perceived as support for a company's storage, manufacturing, and sales needs, not as creators of profits. The center's role in the company's economics has been lowering costs. However, as the logistics' management environment spiraled, along with its storage purpose, developing a new feature of profit creation should be a desirable goal, and to achieve that, value added logistics should be promoted. Logistics centers can also be improved through cost estimation. In the meantime, they have achieved some strides in facility development but have still fallen behind in others, particularly in management functioning. Lax management has been rampant because the industry has not developed a concept of cost estimation. The centers have since made an effort toward unification, standardization, and informatization while realizing cost reductions by establishing systems for effective management, but it has been hard to produce profits. Thus, there is an urgent need to estimate costs by determining a basic cost range for each division of work at logistics centers. This undertaking can be the first step to improving the ineffective aspects of how they operate. Ongoing research and constant efforts have been made to improve the level of effectiveness in the manufacturing industry, but studies on resource management in logistics centers are hardly enough. Thus, a plan to calculate the optimal level of resources necessary to operate a logistics center should be developed and implemented in management behavior, for example, by standardizing the hours of operation. If logistics centers, shippers, related trade groups, academic figures, and other experts could launch a committee to work with the government and maintain an ongoing relationship, the constraint and cooperation among members would help lead to coherent development plans for logistics centers. If the government continues its efforts to provide financial support, nurture professional workers, and maintain safety management, we can anticipate the continuous advancement of logistics centers.

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A Study on the Improvement of Flexible Working Hours (탄력적 근로시간제 개선에 대한 연구)

  • Kwon, Yong-man
    • Journal of Venture Innovation
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    • v.5 no.3
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    • pp.57-70
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    • 2022
  • In modern industrial capitalism, the relationship between the provision of work and the receipt of wages has become an important principle governing society. According to the labor contract, the wages provided by entrusting the right to dispose of one's labor to the employer are directly compensated, and human life should be guaranteed and reproduced with proper rest. The establishment of labor relations under free contracts represents a problem in protecting workers, and accordingly, the maximum of working hours is set as a minimum right for workers, and the standard for minimum rest is set and assigned. The reduction of working hours is very important in terms of the quality of life of workers, but it is also an important issue in efficient corporate activities. As of 2020, Korea has 1,908 hours of annual working hours, the third lowest among OECD 37 countries in the happiness index surveyed by the Sustainable Development Solution Network(SDSN), an agency under the United Nations. Accordingly, the necessity of reducing working hours has been recognized, and the maximum working hours per week has been limited to 52 hours since 2018. In this situation, various working hours are legally excluded as a way to maintain the company's value-added creation and meet the diverse needs of workers, and Korea's Labor Standards Act restricts flexible working hours within three months, flexible working hours exceeding three months, selective working hours, and extended working hours. However, in the discussion on the application of the revised flexible working hours system in 2021 and the expansion of the settlement unit period recently discussed, there is a problem with the flexible working hours system, which needs to be improved. Therefore, this paper aims to examine the problems of the flexible working hours system and improvement measures. The flexible working hours system is a system that does not violate working hours even if the legal working hours are exceeded on a specific day or week according to a predetermined standard, and does not have to pay additional wages for excessive overtime work. It is mainly useful as a form of shift work in manufacturing, sales service, continuous business or electricity, gas, water, and transportation for long-term operations. It is also used as a way to shorten working hours, such as expanding holidays through short working days. However, if the settlement unit period is expanded, it is disadvantageous to workers as the additional wages that workers can receive will not be received. Therefore, First, in order to expand the settlement unit period currently under discussion, additional wages should be paid for the period expanded from the current standard. Second, it is necessary to improve the application of the flexible working hours system to individual workers to have sufficient consultation with individual workers in a written agreement with the worker representative, Third, clarify the allowable time for extended work during the settlement unit period, and Fourth, limit the daily working hours or apply to continuous rest. In addition, since the written agreement of the worker representative is an important issue in the application of the flexible working hours system, it is necessary to secure the representation of the worker representative.