• Title/Summary/Keyword: Energy balance model

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The Policy of Win-Win Growth between Large and Small Enterprises : A South Korean Model (한국형 동반성장 정책의 방향과 과제)

  • Lee, Jang-Woo
    • Korean small business review
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    • v.33 no.4
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    • pp.77-93
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    • 2011
  • Since 2000, the employment rate of small and medium enterprises (SMEs) has dwindled while the creation of new jobs and the emergence of healthy SMEs have been stagnant. The fundamental reason for these symptoms is that the economic structure is disadvantageous to SMEs. In particular, the greater gap between SMEs and large enterprises has resulted in polarization, and the resulting imbalance has become the largest obstacle to improving SMEs' competitiveness. For example, the total productivity has continued to drop, and the average productivity of SMEs is now merely 30% of that of large enterprises, and the average wage of SMEs' employees is only 53% of that of large enterprises. Along with polarization, rapid industrialization has also caused anti-enterprise consensus, the collapse of the middle class, hostility towards establishments, and other aftereffects. The general consensus is that unless these problems are solved, South Korea will not become an advanced country. Especially, South Korea is now facing issues that need urgent measures, such as the decline of its economic growth, the worsening distribution of profits, and the increased external volatility. Recognizing such negative trends, the MB administration proposed a win-win growth policy and recently introduced a new national value called "ecosystemic development." As the terms in such policy agenda are similar, however, the conceptual differences among such terms must first be fully understood. Therefore, in this study, the concepts of win-win growth policy and ecosystemic development, and the need for them, were surveyed, and their differences from and similarities with other policy concepts like win-win cooperation and symbiotic development were examined. Based on the results of the survey and examination, the study introduced a South Korean model of win-win growth, targeting the promotion of a sound balance between large enterprises and SMEs and an innovative ecosystem, and finally, proposing future policy tasks. Win-win growth is not an academic term but a policy term. Thus, it is less advisable to give a theoretical definition of it than to understand its concept based on its objective and method as a policy. The core of the MB administration's win-win growth policy is the creation of a partnership between key economic subjects such as large enterprises and SMEs based on each subject's differentiated capacity, and such economic subjects' joint promotion of growth opportunities. Its objective is to contribute to the establishment of an advanced capitalistic system by securing the sustainability of the South Korean economy. Such win-win growth policy includes three core concepts. The first concept, ecosystem, is that win-win growth should be understood from the viewpoint of an industrial ecosystem and should be pursued by overcoming the issues of specific enterprises. An enterprise is not an independent entity but a social entity, meaning it exists in relationship with the society (Drucker, 2011). The second concept, balance, points to the fact that an effort should be made to establish a systemic and social infrastructure for a healthy balance in the industry. The social system and infrastructure should be established in such a way as to create a balance between short- term needs and long-term sustainability, between freedom and responsibility, and between profitability and social obligations. Finally, the third concept is the behavioral change of economic entities. The win-win growth policy is not merely about simple transactional relationships or determining reasonable prices but more about the need for a behavior change on the part of economic entities, without which the objectives of the policy cannot be achieved. Various advanced countries have developed different win-win growth models based on their respective cultures and economic-development stages. Japan, whose culture is characterized by a relatively high level of group-centered trust, has developed a productivity improvement model based on such culture, whereas the U.S., which has a highly developed system of market capitalism, has developed a system that instigates or promotes market-oriented technological innovation. Unlike Japan or the U.S., Europe, a late starter, has not fully developed a trust-based culture or market capitalism and thus often uses a policy-led model based on which the government leads the improvement of productivity and promotes technological innovation. By modeling successful cases from these advanced countries, South Korea can establish its unique win-win growth system. For this, it needs to determine the method and tasks that suit its circumstances by examining the prerequisites for its success as well as the strengths and weaknesses of each advanced country. This paper proposes a South Korean model of win-win growth, whose objective is to upgrade the country's low-trust-level-based industrial structure, in which large enterprises and SMEs depend only on independent survival strategies, to a high-trust-level-based social ecosystem, in which large enterprises and SMEs develop a cooperative relationship as partners. Based on this objective, the model proposes the establishment of a sound balance of systems and infrastructure between large enterprises and SMEs, and to form a crenovative social ecosystem. The South Korean model of win-win growth consists of three axes: utilization of the South Koreans' potential, which creates community-oriented energy; fusion-style improvement of various control and self-regulated systems for establishing a high-trust-level-oriented social infrastructure; and behavioral change on the part of enterprises in terms of putting an end to their unfair business activities and promoting future-oriented cooperative relationships. This system will establish a dynamic industrial ecosystem that will generate creative energy and will thus contribute to the realization of a sustainable economy in the 21st century. The South Korean model of win-win growth should pursue community-based self-regulation, which promotes the power of efficiency and competition that is fundamentally being pursued by capitalism while at the same time seeking the value of society and community. Already existing in Korea's traditional roots, such objectives have become the bases of the Shinbaram culture, characterized by the South Koreans' spontaneity, creativity, and optimism. In the process of a community's gradual improvement of its rules and procedures, the trust among the community members increases, and the "social capital" that guarantees the successful control of shared resources can be established (Ostrom, 2010). This basic ideal can help reduce the gap between large enterprises and SMEs, alleviating the South Koreans' victim mentality in the face of competition and the open-door policy, and creating crenovative corporate competitiveness. The win-win growth policy emerged for the purpose of addressing the polarization and imbalance structure resulting from the evolution of 21st-century capitalism. It simultaneously pursues efficiency and fairness on one hand and economic and community values on the other, and aims to foster efficient interaction between the market and the government. This policy, however, is also evolving. The win-win growth policy can be considered an extension of the win-win cooperation that the past 'Participatory Government' promoted at the enterprise management level to the level of systems and culture. Also, the ecosystemic development agendum that has recently emerged is a further extension that has been presented as a national ideal of "a new development model that promotes the co-advancement of environmental conservation, growth, economic development, social integration, and national and individual development."

Aerodynamic and Aeroelastic Tool for Wind Turbine Applications

  • Viti, Valerio;Coppotelli, Giuliano;De Pompeis, Federico;Marzocca, Pier
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.1
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    • pp.30-45
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    • 2013
  • The present work focuses on the unsteady aerodynamics and aeroelastic properties of a small-medium sized wind-turbine blade operating under ideal conditions. A tapered/twisted blade representative of commercial blades used in an experiment setup at the National Renewable Energy Laboratory is considered. The aerodynamic loads are computed using Computational Fluid Dynamics (CFD) techniques. For this purpose, FLUENT$^{(R)}$, a commercial finite-volume code that solves the Navier-Stokes and the Reynolds-Averaged Navier-Stokes (RANS) equations, is used. Turbulence effects in the 2D simulations are modeled using the Wilcox k-w model for validation of the CFD approach. For the 3D aerodynamic simulations, in a first approximation, and considering that the intent is to present a methodology and workflow philosophy more than highly accurate turbulent simulations, the unsteady laminar Navier-Stokes equations were used to determine the unsteady loads acting on the blades. Five different blade pitch angles were considered and their aerodynamic performance compared. The structural dynamics of the flexible wind-turbine blade undergoing significant elastic displacements has been described by a nonlinear flap-lag-torsion slender-beam differential model. The aerodynamic quasi-steady forcing terms needed for the aeroelastic governing equations have been predicted through a strip-theory based on a simple 2D model, and the pertinent aerodynamic coefficients and the distribution over the blade span of the induced velocity derived using CFD. The resulting unsteady hub loads are achieved by a first space integration of the aeroelastic equations by applying the Galerkin's approach and by a time integration using a harmonic balance scheme. Comparison among two- and three- dimensional computations for the unsteady aerodynamic load, the flap, lag and torsional deflections, forces and moments are presented in the paper. Results, discussions and pertinent conclusions are outlined.

Novel Model Predictive Control Method to Eliminate Common-mode Voltage for Three-level T-type Inverters Considering Dead-time Effects

  • Wang, Xiaodong;Zou, Jianxiao;Dong, Zhenhua;Xie, Chuan;Li, Kai;Guerrero, Josep M.
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1458-1469
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    • 2018
  • This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT2Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the $3LT^2Is$ can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.

Projection of the Climate Change Effects on the Vertical Thermal Structure of Juam Reservoir (기후변화가 주암호 수온성층구조에 미치는 영향 예측)

  • Yoon, Sung Wan;Park, Gwan Yeong;Chung, Se Woong;Kang, Boo Sik
    • Journal of Korean Society on Water Environment
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    • v.30 no.5
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    • pp.491-502
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    • 2014
  • As meteorology is the driving force for lake thermodynamics and mixing processes, the effects of climate change on the physical limnology and associated ecosystem are emerging issues. The potential impacts of climate change on the physical features of a reservoir include the heat budget and thermodynamic balance across the air-water interface, formation and stability of the thermal stratification, and the timing of turn over. In addition, the changed physical processes may result in alteration of materials and energy flow because the biogeochemical processes of a stratified waterbody is strongly associated with the thermal stability. In this study, a novel modeling framework that consists of an artificial neural network (ANN), a watershed model (SWAT), a reservoir operation model(HEC-ResSim) and a hydrodynamic and water quality model (CE-QUAL-W2) is developed for projecting the effects of climate change on the reservoir water temperature and thermal stability. The results showed that increasing air temperature will cause higher epilimnion temperatures, earlier and more persistent thermal stratification, and increased thermal stability in the future. The Schmidt stability index used to evaluate the stratification strength showed tendency to increase, implying that the climate change may have considerable impacts on the water quality and ecosystem through changing the vertical mixing characteristics of the reservoir.

3-Dimensional Hydrodynamic and Water Quality Change Simulation of Jingyang Reservoir Using EFDC-WASP (EFDC-WASP을 이용한 진양호의 3차원 수리.수질 변화 모의)

  • Jeong, Young-Won;Kim, Young-Do;Kim, Jeong-Kon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.1079-1083
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    • 2010
  • Due to summer rainfall is concentrated in the construction of the reservoir and the dam was inevitable. The character of these structures are different from the common rivers have been characterized. According to this problem, we need to adopt to this area with three dimensional model. Construction of dams for preservation of land, utilization of water resources, and exploitation of energy potential, which is a basic element of countries' development, is regarded as indispensable for peoples. In addtion, the development of the Nakdong River nutrient and pathogen Total Maximum Daily Loads (TMDL) required that the full range of pollutants, sources, and flow conditions, typical of heavily urbanized areas, be addressed for a single water body with 1-D simulation model (river) and 3-D simulation model (reservoir). The objective of this study is to simulate the applicability of reservoir with the coupling of 3-D hydrodynamic and water quality models to estimate water balance and pollutant loading in Namgang Dam(Jinyang reservoir).

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Methane emission from municipal solid waste dumpsites: A case study of Chennai city in India

  • Srinivasan, Pavithrapriya;Andimuthu, Ramachandran;S.N., Ahamed Ibrahim;Ramachandran, Prasannavenkatesh;Rajkumar, Easwari;Kandasamy, Palanivelu
    • Advances in environmental research
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    • v.9 no.2
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    • pp.97-107
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    • 2020
  • The indiscriminate growth in global population poses a threat to the world in handling and disposal of Municipal solid waste. Rapid urban growth increases the production, consumption and generation of Municipal solid waste which leads to a drastic change in the environment. The methane produced from the Municipal Solid waste accounts for up to 11% global anthropogenic emissions, which is a major cause for global warming. This study reports the methane emission estimation using IPCC default, TNO, LandGEM, EPER and close flux chamber from open dump yards at Perungudi and Kodungaiyur in Chennai, India. The result reveals that the methane emission using close flux chamber was in the range of 8.8 Gg/yr-11.3 Gg/yr and 6.1Gg/yr to 9.1 Gg/yr at Kodungaiyur and Perungudi dump yard respectively. The per capita waste generation was estimated based on waste generation and population. The waste generation potential was projected using linear regression model for the period 2017-2050. The trend of CH4 emission in the actual field measurement were increased every year, similarly the emission trend also increased in IPCC default method (mass balance approach), EPER Germany (zero order decay model) where as TNO and Land GEM (first order decay model) were decreased. The present study reveals that Kodungaiyur dump yard is more vulnerable to methane emission compared to Perungudi dump yard and has more potential in waste to energy conversion mechanisms than compare to Perungudi dump yard.

Design of Ultra Low-Voltage NCL Circuits in Nanoscale MOSFET Technology (나노 MOSFET 공정에서의 초저전압 NCL 회로 설계)

  • Hong, Woo-Hun;Kim, Kyung-Ki
    • Journal of Korea Society of Industrial Information Systems
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    • v.17 no.4
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    • pp.17-23
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    • 2012
  • Ultra low-power design and energy harvesting applications require digital systems to operate under extremely low voltages approaching the point of balance between dynamic and static power consumption which is attained in the sub-threshold operation mode. Delay variations are extremely large in this mode. Therefore, in this paper, a new low-power logic design methodology using asynchronous NCL circuits is proposed to reduce power consumption and not to be affected by various technology variations in nanoscale MOSFET technology. The proposed NCL is evaluated using various benchmark circuits at 0.4V supply voltage, which are designed using 45nm MOSFET predictive technology model. The simulation results are compared to those of conventional synchrouns logic circuits in terms of power consumption and speed.

A New Method to Retrieve Sensible Heat and Latent Heat Fluxes from the Remote Sensing Data

  • Liou Yuei-An;Chen Yi-Ying;Chien Tzu-Chieh;Chang Tzu-Yin
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.415-417
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    • 2005
  • In order to retrieve the latent and sensible heat fluxes, high-resolution airborne imageries with visible, near infrared, and thermal infrared bands and ground-base meteorology measurements are utilized in this paper. The retrieval scheme is based on the balance of surface energy budget and momentum equations. There are three basic surface parameters including surface albedo $(\alpha)$, normalized difference vegetation index (NOVI) and surface kinetic temperature (TO). Lowtran 7 code is used to correct the atmosphere effect. The imageries were taken on 28 April and 5 May 2003. From the scattering plot of data set, we observed the extreme dry and wet pixels to derive the fitting of dry and wet controlled lines, respectively. Then the sensible heat and latent heat fluxes are derived from through a partitioning factor A. The retrieved latent and sensible heat fluxes are compared with in situ measurements, including eddy correlation and porometer measurements. It is shown that the retrieved fluxes from our scheme match with the measurements better than those derived from the S-SEBI model.

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Droop Control Scheme of a Three-phase Inverter for Grid Voltage Unbalance Compensation

  • Liu, Hongpeng;Zhou, Jiajie;Wang, Wei;Xu, Dianguo
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1245-1254
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    • 2018
  • The stability of a grid-connected system (GCS) has become a critical issue with the increasing utilization of renewable energy sources. Under grid faults, however, a grid-connected inverter cannot work efficiently by using only the traditional droop control. In addition, the unbalance factor of voltage/current at the common coupling point (PCC) may increase significantly. To ensure the stable operation of a GCS under grid faults, the capability to compensate for grid imbalance should be integrated. To solve the aforementioned problem, an improved voltage-type grid-connected control strategy is proposed in this study. A negative sequence conductance compensation loop based on a positive sequence power droop control is added to maintain PCC voltage balance and reduce grid current imbalance, thereby meeting PCC power quality requirements. Moreover, a stable analysis is presented based on the small signal model. Simulation and experimental results verify the aforementioned expectations, and consequently, the effectiveness of the proposed control scheme.

Water Quality Improvement System Using High Voltage Electric Field with Self-Generation System (자가 발전 시스템을 갖춘 고전압 전기장 수질개선 장치 개발)

  • Kang, Rae-Yun;Kang, Chul-Ung
    • Journal of Power System Engineering
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    • v.19 no.2
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    • pp.84-89
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    • 2015
  • The occurrence of algae caused by eutrophication of fresh water is a pollution source to destroy the aquatic environment. When the high voltage electric field is applied in the water, When a high voltage is applied to the electric field in the water, the algae can be broken the balance of cell membranes, and is dead. In this paper, we develop a water quality improvement system for generating an electric field having a higher energy than the zeta potential when a high voltage is applied to 4,000V. To ensure the mobility of the water quality improvement system, we designed the PV generation system using the optimal size technique that is based on the model of power lack ratio. By evaluating the output characteristics of the water quality improvement system, power generation characteristics of the PV generation system, and battery charging characteristics, we can show that the proposed system can be applicable to the water quality improvement system inhibiting the growth rate of the algae in the fresh water.