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The stray loss in a transformer structure is difficult to measure. Thus, it is very important to predict the loss accurately by numerical modeling. This article deals with numerical modeling and experiments for the prediction of the stray loss in power transformer tank. Before numerical analysis, the finite-element model should be verified in advance. In this article, results from finite element analysis (FEA) were compared with those from experiments by using a prototype model. Experiments were carried out by changing the wall shunt thickness by turns. The magnetic flux density obtained from the experiment is compared and agreed well with those predicted by 3-D FEA. After verifying the validity of FEA, the actual transformer was modeled and the wall shunt was applied to the tank to reduce the stray loss.

Power utilities worldwide commonly use the radial distribution system because of its advantages of being simple in structure and having relatively inexpensive installation costs. It has a disadvantage in that its power supply reliability is low because the load side of the fault section will suffer from an outage in the event of a fault in the system. However, recently, with ICT (Information and Communication Technologies) development, system reliability is required to be high as the outage-susceptible loads increase. In addition, the increase in the connection of distributed resources such as renewable energy and electric vehicles is making it impossible to predict the power flow and reducing line utilization. Therefore, a loop power distribution system is proposed as a measure to solve this problem. Because all buses (nodes) in a loop distribution system have two or more power supply routes, they are more reliable than the radial system. It allows them to improve line utilization by connecting lines with different load peak times. However, in the case of a fault in the loop distribution system, the fault current is supplied from both directions, making it impossible to properly isolate the fault section with the protection method of the conventional distribution system. The permissive overreach transfer trip (POTT) method using communication to compensate for the limitations of conventional protection devices, and the other method using directional distance relay, is proposed. However, these methods operate by determining the direction of the fault current but have a disadvantage. It is difficult to detect a fault due to the effects of ground faults and distributed generation (DG) occurring in other lines. Therefore, in this paper, we propose a protection coordination algorithm that uses the negative-sequence component of voltage and current that occur when an unbalanced fault occurs, rather than the determination of the directionality and use of communication. To validate this, we configured a system using PSCAD/EMTDC (Manitoba Hydro International Ltd., Winnipeg, Manitoba, Canada), a system analysis program package and verified the results depending on the type of faults with the proposed algorithm.

Stand-alone microgrids integrating renewable energy sources have emerged as an efficient energy solution for electrifying isolated sites, such as islands and remote areas. The design of a microgrid involves various influential factors, including technological development, economic feasibility, and environmental impacts, based on the conditions and regulations of a particular site. This paper proposes a comprehensive microgrid design framework based on power system analysis and techno-economic analysis. The obtained optimal microgrid configuration satisfies both the design objective and power system performance regulations. The proposed design approach focuses on using practical data and can adapt to any microgrid design problems based on the local characteristics of a specific site. The practicality and effectiveness of the design framework are validated by applying it to the design of a stand-alone microgrid for Deokjeok Island in South Korea. The case study results justify the importance of considering site-specific characteristics and the impacts of power system conditions on the optimal microgrid design.

This paper proposes a novel channel estimation technique for the offset quadrature amplitude modulation based filter bank multi-carrier (FBMC/OQAM) systems. Unlike the conventional approaches, the proposed pilot signals utilize their intrinsic interference for the channel estimation, and provide an improved power efficiency compared to the conventional auxiliary pilot method. However, due to the non-whiteness of the noise components at the output of the analysis filter banks, the power gain obtained by the proposed scheme cannot be maximized. To overcome this difficulty, we propose a semiblind channel estimation by grouping the pilot signals and imposing sign ambiguities to them. Theoretical analysis shows that the proposed semiblind channel estimation remarkably improves the power efficiency of its non-semiblind version. Finally, it is demonstrated that the near optimum detection performance is achieved by the proposed scheme at a reduced complexity.

Most power systems at islands in South Korea are stand-alone microgrids, which are disconnected from main grid, and generally have small power demand. Although the diesel generator has many advantages as main power sources for small power system, it has problems of very high operational and maintenance cost. To solve these problems, the South Korean government has replaced conventional diesel generators with renewable energies based on converter-based generators. In this study, the power system in Dukjuk Island in South Korea is modeled in detail based on practical data. Then, the voltage and frequency responses of the stand-alone microgrid are analysed corresponding to the penetration ratio of total diesel generation.

This study proposes an energy management system (EMS) for stable operation of isolated microgrid which is composed of diesel generators, wind turbines, photovoltaic generation systems and battery energy storage systems (BESS). In the EMS, a power dispatch control is proposed in order to minimise diesel operation. There is also a state-of-charge (SOC) control to allow continuous use of the BESS. By dispatching the scheduled power of the diesel generators, the SOC can be regulated within its limits. A simulation model for isolated microgrid was developed using DIgSILENT Power Factory® software. To verify the performance of the proposed EMS, case studies are performed using practical data of Dukjuk Island in Korea.

The aim of this study was to investigate the neuroprotective effect of mulberrofuran G (MG) in in vitro and in vivo models of cerebral ischemia. MG was isolated from the root bark of Morus bombycis. MG inhibited nicotinamide adenine dinucleotide phosphate oxidase (NOX) enzyme activity and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced NOX4 protein expression in SH-SY5Y cells. MG inhibited the expression of activated caspase-3 and caspase-9 and cleaved poly adenine dinucleotide phosphate-ribose polymerase in OGD/R-induced SH-SY5Y cells. In addition, MG protected OGD/R-induced neuronal cell death and inhibited OGD/R-induced reactive oxygen species generation in SH-SY5Y cells. In in vivo model, MG-treated groups (0.2, 1, and 5 mg/kg) reduced the infarct volume in middle cerebral artery occlusion/reperfusion-induced ischemic rats. The MG-treated groups also reduced NOX4 protein expression in middle cerebral artery occlusion/reperfusion-induced ischemic rats. Furthermore, protein expression of 78-kDa glucose-regulated protein/binding immunoglobulin protein, phosphorylated IRE1α, X-box-binding protein 1, and cytosine enhancer binding protein homologous protein, mediators of endoplasmic reticulum stress, were inhibited in MG-treated groups. Taken together, MG showed protective effect in in vitro and in vivo models of cerebral ischemia through inhibition of NOX4-mediated reactive oxygen species generation and endoplasmic reticulum stress. This finding will give an insight that inhibition of NOX enzyme activity and NOX4 protein expression could be a new potential therapeutic strategy for cerebral ischemia. Copyright © 2016 John Wiley & Sons, Ltd.

The ways of present transformer design can be divided into two types: using spreadsheet like Excel and using design software. Our first work is to develop the design software that can be used by small companies for free. We developed design software which generates as many designs as possible, without aid of expert's knowledge. Our second work is to improve efficiency by parallelizing the repetitive calculations. The performance of our design software is evaluated by comparing the results obtained from different numbers of cores. We show improvement of execution time where execution of 4 cores is about 45% faster than that of 1 core.

The efficiency of transformers is critical to save electrical energy. There are three types of current transformer design methods. The current methods have problems. In this paper, we described current ways of designing a transformer, and we also explained their weakness. To overcome these weakness, we apply deep learning to designing a transformer. This paper also shows that our model recommend design parameters to satisfy design specification.

Modular construction, which involves factory-based modular unit manufacturing followed by installation at a construction site, has been recognized as one of the sustainable construction methods. Its advantages are known to be implemented through (1) standardized design, (2) standardized production method, and (3) large-scale development (mass production system). These three conditions are basic requirements for modular construction market expansion, but it is difficult to define that these conditions are a prerequisite for judging whether modular construction applied or not. Nevertheless, public development companies in regions or countries where modular construction has just begun thought that modular construction should meet all three conditions that are suitable for applying public construction projects. This is because it is difficult to compare conventional construction projects with similar conditions to modular construction projects. This paper analyzes the cost and duration data of three small-scale public construction rental housing (PCRH) projects involving modular construction in Korea. These cases presented herein include a public college student dormitory, public low-rise rental housing, and public mid-rise rental housing in small-scale development projects. Those were applied not standardized design (common design and regulation), but were reflected in each project&rsquo, s demands (different design and regulation). To compare it, this paper analyzed 91 public housing provision projects&rsquo, construction data from 2011 to 2017 from one of the public rental housing provision companies in Korea. Among them, 19 small-scale public rental housing data were extracted for comparing with modular construction project data. The results show that, even if not standardized, the design and production process, and modular construction durations, were more effective&mdash, but costs were similar or expensive. Based on the conclusion drawn from three cases, this paper presents important considerations for the application of modular construction in other small-scale public construction rental housing projects from the perspective of public development companies.

본 연구는 꾸지뽕나무 열매에서 분리 및 정제한 isoflavonoid 성분에 대하여 Ultra Performance Liquid Chromatography(UPLC)을 이용하여 분석법을 개발하고 검증하고자 하였다. 꾸지뽕나무 열매를 methanol로 추출하여 n-hexane, ethylacetate, 물 순으로 분액 후, ethyl acetate 추출물을 silica gel 컬럼과 sephadex LH-20 컬럼을 사용하여 4종의 isoflavonoid들을 분리하였다. 분리한 4종의 isoflavonoid들은 기기분석(UV-Vis spectroscopy, ESI-MS, 1H NMR, 13CNMR)을 통하여 alpinumisoflavone, 6,8-diprenyl orobol, 6,8-diprenyl genistein, 4.-O-methylalpinumisoflavone으로 확인 및 동정하였다. 이 성분들을 2% acetic acid 용액(용매 A)과 2% acetic acid가 함유된 MeOH 용액(용매 B)을 기울기이동상으로 하여 C18 컬럼이 장착된 UPLC로 분석하였다. 분석 조건은 ICH (International Conference on Harmonisation)가이드라인에 기술된 선택성, 직선성, 정량한계, 검출한계, 정확성 및 정밀성을 측정하여 분석법의 타당성을 검증하였다. 또한 검증한 분석방법을 이용하여 꾸지뽕나무 열매의 채취시기별 함량을 조사하였다. 그 결과, 미숙과는 7월과 8월에 각 성분의 함량이 증가하였다가 9월에는 감소하였고, 성숙과의 경우 9월 미숙과 보다 각 성분들이 전반적으로 많이 함유되어 있었다.

An ATSC 3.0 physical layer frame consists of a bootstrap immediately followed by a preamble containing layer 1 control signaling and then one or more subframes carrying payload data. Subframes within a particular frame may be of the same or different types, with different subframe types being configured for different classes of receivers (e.g., mobile versus fixed). This paper focuses on the subframe structure, configuration, and contents, including subframe boundary symbols which carry additional pilots to assist with channel estimation at the receiver and cell multiplexing which maps physical layer pipe (PLP) payload data to physical layer resources within each subframe. Various methods for cell multiplexing multiple PLPs within a subframe are discussed and described, including time division multiplexing, frequency division multiplexing, time-frequency division multiplexing, and layered division multiplexing. Frequency interleaving, pilot insertion, and guard interval insertion are also covered, including a method of distributing extra samples to guard intervals in order to obtain frame lengths equal to an integer number of milliseconds.

Reliability is an important index which determines the power service and quality provided to customers. As the demand increases continuously and the system changes in accordance with the environmental regulation, the reliability assessment in the distribution system becomes crucial. In this paper, we propose methods for improving the reliability of the distribution system using electric vehicles (EVs) in the system. In this paper, EVs are used as power supplying devices, such as a transportable energy storage system (ESS) which supplies power when fault occurs in the system, and by using a time–space network (TSN) in particular, EV capacity in accordance with the load arrival time was calculated. Unlike other existing reliability assessments, we did not use the average load of customers. Instead, by taking into account the load pattern by times, we considered the priority for load supply in accordance with the failure scenarios and failure times. Based on the priority calculated for each time of failure and failure scenario, plans for EV operation to minimize expected customer interruption cost (ECOST), the reliability index in the distribution system, were established. Finally, a case study was performed using the IEEE RBTS (Roy Billinton Test System) 2 Bus and the performance of the model proposed in this paper was verified based on the result.

Optimal operation of the battery energy storage system (BESS) is very important to reduce the running cost of a microgrid. Rolling horizon-based scheduling, which updates the optimal decision based on the latest information, is widely applied to microgrid operation. In this paper, the optimal scheduling of a microgrid, considering the energy cost, demand charge, and the battery wear-cost, is formulated as a mixed integer linear programming (MILP) problem. This paper also deals with two practical and important issues when applying the rolling-horizon strategy to BESS scheduling. First, to mitigate the high dependency of the load forecast on the latest information, a confidence weight parameter method is proposed. Second, a new target state of charge (SOC) assignment method is proposed to avoid the depletion of BESS and to reduce the wear-cost of the battery. In addition to the optimal scheduling, a novel real-time control scheme is proposed to mitigate the effect of the forecast uncertainty. The performance of the proposed methods is tested with data measured from a campus microgrid.

In this paper the operational characteristics of stand-alone microgrid was analyzed using RTDS simulation models. The accuracy of developed simulation models were verified by comparing with the analysis results using the PSCAD/EMTDC simulation models. The proper scenarios and operation algorithms were developed and analyzed in accordance with various situations that can occur in the actual system, so as to establish operation scheme for the stand-alone microgrid system. The developed simulation models can be effectively utilized to design a newly installed stand-alone microgrid and to develop various operation scenarios for stand-alone microgrid. And these models can be applied for analyzing the transient phenomena due to system fault so that system protection can be properly designed.

α-Viniferin is an oligostilbene of trimeric resveratrol and has anticancer activity; however, the molecular mechanism underlying the anti-inflammatory effects of α-viniferin has not been completely elucidated thus far. Therefore, we determined the mechanism by which α-viniferin regulates lipopolysaccharide (LPS)-induced expression of proinflammatory mediators in BV2 microglial cells. Treatment with α-viniferin isolated from Clematis mandshurica decreased LPS-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2). α-Viniferin also downregulated the LPS-induced expression of proinflammatory genes such as iNOS and COX-2 by suppressing the activity of nuclear factor kappa B (NF-κB) via dephosphorylation of Akt/PI3K. Treatment with a specific NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), indirectly showed that NF-κB is a crucial transcription factor for expression of these genes in the early stage of inflammation. Additionally, our results indicated that α-viniferin suppresses NO and PGE2 production in the late stage of inflammation through induction of heme oxygenase-1 (HO-1) regulated by nuclear factor erythroid 2-related factor (Nrf2). Taken together, our data indicate that α-viniferin suppresses the expression of proinflammatory genes iNOS and COX-2 in the early stage of inflammation by inhibiting the Akt/PI3K-dependent NF-κB activation and inhibits the production of proinflammatory mediators NO and PGE2 in the late stage by stimulating Nrf2-mediated HO-1 signaling pathway in LPS-stimulated BV2 microglial cells. These results suggest that α-viniferin may be a potential candidate to regulate LPS-induced inflammation.