• 자원ㆍ환경경제연구
• /
• 제16권2호
• /
• pp.313-336
• /
• 2007

본 연구는 북한경제관련 전문기관이나 전문가들의 연구결과와 불완전하게나마 발표되거나 간접적으로 도출된 북한의 통계자료들을 통계학적인 방법으로 통합하여 에너지 부문이 구분된 북한의 2005년도 산업연관표를 추정하였다. 이렇게 추정된 산업연관표를 이용하여 에너지 부문에 대한 대북투자가 북한경제의 산업별 산출과 부가가치에 미치는 효과를 투입-산출 분석과 CGE 분석을 이용하여 계산하였다. 전력산업에 대한 40억 달러의 대북투자는 총산출을 3억 6,802만 달러 증가시키고 총부가가치를 1억 5,599만 달러 증가시키는 것으로 계산되었고 석유산업에 대한 1.5억 달러의 대북투자는 총산출을 2,046만 달러 증대시키고 총부가가치를 965만 달러 증가시키는 것으로 나타났다.

• 농업과학연구
• /
• 제50권3호
• /
• pp.395-406
• /
• 2023

The large amount of energy required for successful crop production is the main challenge in greenhouse cropping systems. As a response to this challenge a comprehensive evaluation of greenhouse energy consumption was carried out in two structurally similar single-span greenhouses with different thermal curtain positions, with particular attention to energy productivity, specific energy, net energy, and energy ratio. The greenhouses are used for strawberry production. In the R-greenhouse (RGH), the thermal curtain hanged directly at the roof ridge, whereas in the Q-greenhouse (QGH), the thermal curtain was placed 5° from an imaginary vertical axis, from the middle of the roof ridge downwards to the north side of the greenhouse roof. The relevant data were recorded using standard methods. The results indicated that the energy expended in the RGH and QGH systems was 2,186.48 and 2,189.26 MJ/m², respectively. Electricity and nitrogen fertilizer contributed the highest energy input in both greenhouses and in all seasons. The output energy was 3.12 and 3.82 MJ/m², respectively, in RGH and QGH in season I and 4.40 and 4.87 MJ/m² in season II. In terms of energy expended, there was no significant difference between the two greenhouses, nor between the two seasons. These results indicate that greenhouses of the size used in this investigation are not viable in terms of energy productivity, energy-use efficiency, and subsequent economic performance. However, further studies should be conducted to scale-up the information obtained from this investigation.

• Journal of Power Electronics
• /
• 제19권3호
• /
• pp.665-675
• /
• 2019

Renewable energy based on photovoltaic systems is beginning to play an important role to supply power to remote areas all over the world. Owing to the lower output voltage of photovoltaic arrays, high gain DC-DC converters with a high efficiency are required in practice. This paper presents a novel interleaved DC-DC boost converter with a high voltage gain, where the input terminal is interlaced in parallel and the output terminal is staggered in series (IPOSB). The IPOSB configuration can reduce input current ripples because two inductors are interlaced in parallel. The double output capacitors are charged in staggered parallel and discharged in series for the load. Therefore, IPOSB can attain a high step-up conversion and a lower output voltage ripple. In addtion, the output voltage can be automatically divided by two capacitors, without the need for extra sharing control methods. At the same time, the voltage stress of the power devices is lowered. The inrush current problem of capacitors is restrained by the inductor when compared with high gain converters with a switching-capacitor structure. The working principle and steady-state characteristics of the converter are analyzed in detail. The correctness of the theoretical analysis is verified by experimental results.

• Journal of Power Electronics
• /
• 제15권1호
• /
• pp.10-17
• /
• 2015

A quasi-constant on-time controlled buck front end in combined discontinuous conduction mode and boundary conduction mode is proposed to improve power factor (PF).When instantaneous AC input voltage is lower than the output bus voltage per period, the buck converter turns into buck-boost converter with the addition of a level comparator to compare input voltage and output voltage. The gate drive voltage is provided by an additional oscillator during distortion time to eliminate the cross-over distortion of the input current. This high PF comes from the avoidance of the input current distortion, thereby enabling energy to be delivered constantly. This paper presents a series analysis of controlling techniques and efficiency, PF, and total harmonic distortion. A comparison in terms of efficiency and PF between the proposed converter and a previous work is performed. The specifications of the converter include the following: input AC voltage is from 90V to 264V, output DC voltage is 80V, and output power is 94W.This converter can achieve PF of 98.74% and efficiency of 97.21% in 220V AC input voltage process.

• 한국융합학회논문지
• /
• 제7권4호
• /
• pp.191-198
• /
• 2016

국가 기간산업 중 하나인 전력산업은 산출물인 전력을 각 산업부문에 중간재로 공급하고 있으므로 전력의 공급지장이 국민경제에 미치는 영향은 큰 편이다. 만약 전력 공급이 원활치 못하게 되면 직접적으로는 생산 차질, 원료 공급 불안, 각종 장비 고장 등의 생산 및 공정상의 문제를 일으키고 간접적으로는 생산 차질에 따른 전력 관련 산업의 생산 손실부터 실업 및 물가 상승 등의 문제까지 등장할 수 있다. 이에 본 논문에서는 전력산업 산출물 1원어치의 공급지장이 타 산업에 미치는 부정적 생산차질 효과를 의미하는 공급지장효과를 분석하고자 한다. 이를 위해 산업간 중간재의 흐름을 하나의 표로 나타낸 산업연관표를 활용한 산업연관분석을 적용하고자 한다. 보다 구체적으로는 OECD 주요국을 대상으로 공급유도형 모형을 활용하여 공급지장 효과를 분석한다. 공급지장효과의 값은 덴마크가 1.682로 가장 크며 다음으로 한국, 일본, 호주, 영국 순으로 나타났다.

• Journal of Power Electronics
• /
• 제17권6호
• /
• pp.1391-1401
• /
• 2017

In this paper, a secondary resonance half-bridge dc-dc converter with an inductive output filter is presented. The primary side of such a converter utilizes asymmetric pulse width modulation (APWM) to achieve zero-voltage switching (ZVS) of the switches, and clamps the voltage of the switch to the input voltage. In addition, zero current switching (ZCS) of the output diode is achieved by a half-wave rectifier circuit with a filter inductor and a resonant branch in the secondary side of the proposed converter. Thus, the switching losses and diode reverse-recovery losses are eliminated, and the performance of the converter can be improved. Furthermore, an inductive output filter exists in the converter reduce the output current ripple. The operational principle, performance analysis and design equation of this converter are given in this paper. The analysis results show that the output diode voltage stress is independent of the duty cycle, and that the voltage gain is almost linear, similar to that of the isolation Buck-type converter. Finally, a 200V~380V input, 24V/2A output experimental prototype is built to verify the theoretical analysis.

• 지역연구
• /
• 제34권4호
• /
• pp.61-74
• /
• 2018

본 연구의 목적은 스마트시티 산업의 융합변화를 분석하는 것이다. 스마트시티의 연관 산업은 정보통신기술 및 지식 기반의 건설 산업으로 정의할 수 있다. 본 연구는 1980년, 2014년 한국은행에서 발표한 산업연관표를 이용하여 투입산출분석과 구조경로분석을 수행하였다. 산업연관표 자료는 2개년도 비교분석을 위해 국내총생산 가격수정인자(GDP Deflator)가 적용되었다. 산업의 분류는 403개 산업을 기준으로 27개 그리고 8개 산업으로 분류되었다. 분석 결과는 다음과 같다. 첫째, 투입산출계수 분석에 따르면, 정보통신 서비스 산업(ITS)과 에너지 공급 산업(EnS)은 건설 산업에 투입량이 증가되었다. 반면에 지식 서비스 산업(KS)과 기타 서비스 산업(EtS)은 감소하였다. 둘째, 생산유발계수 분석 결과, 건설 산업(C)은 정보통신 서비스 산업(ITS), 에너지 공급 산업(EnS), IT 제조 산업(ITM) 그리고 비 IT 제조 산업(NITM) 순으로 직 간접적인 영향을 미쳤으며, 가장 큰 변화량을 보인 산업은 정보통신 서비스 산업(ITS)으로 분석되었다. 셋째, 구조경로분석 결과, 스마트시티 산업은 117개의 새로운 생산경로를 만들었으며, 구조적 세분화를 이끌어내고 있었다. 산업의 융합변화는 정보통신 서비스 산업(ITS), 에너지 공급 산업(EnS), 비 IT 제조업(NITM), IT 제조업(ITM)을 중심으로 진행되고 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권4호
• /
• pp.1889-1910
• /
• 2017

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance.

• 한국주거학회:학술대회논문집
• /
• 한국주거학회 2006년도 추계학술발표대회 논문집
• /
• pp.275-280
• /
• 2006

The protection of the environment is one of today's key demanding international activities and interests. All of aspects including industry, economy and society should be changed into environmental friendly industries. The building is not exception in this trend. What is not generally realized is that building, in the lifecycle of construction, use and demolition, account for large construction, not considered with environment impact and conservation in the lifecycle. Expecially, the construction materials and components used in the construction stage has much embodied energy. And much $CO_2$ emit on the production of the construction material and component. The energy use and $CO_2$ emission would continuously diminish the limited natural resources and impact the environment such as ozon layer destruction. In this paper, it studied the estimation of the amount of energy use and $CO_2$ emission in the building construction stage, it would provide the estimation process and applied with the multifamily housing.

• Nuclear Engineering and Technology
• /
• 제41권4호
• /
• pp.549-560
• /
• 2009

Over the last three decades, nuclear technology development has played a vital role in the socio-economic development of the Republic of Korea. This study, being the first of its kind, focuses on quantifying the actual economic contribution of nuclear technologies to economic development by evaluating the net benefit of the nuclear power with respect to the country's Gross Domestic Product (GDP). An input-output analysis was employed as a methodological approach to analyze inter-industrial economic activities by calculating the industrial value added as a means of the economic contribution during the period of 1980 to 2005. The industrial value added of nuclear technologies was estimated from the construction and operation of nuclear power (backward-linked industrial value added) and from the industrial activities attributed to the electricity generated by the nuclear power (forward-linked industrial value added). It was found that the total net contribution of nuclear technologies as a percentage share of GDP amounted to 2.38% in 2005.