가중치법을 이용한 SWE-SM(Slipring-less Winding Excited Synchronous Machine)의 다목적 최적설계

박지산(Ji-San Park),변진규(Jin-Kyu Byun) 한국자기학회 2022 韓國磁氣學會誌 Vol.32 No.1

SWE-SMs (Slipring-less Winding Excited Synchronous Machines) have low price and sturdy rotor structure, and there are ongoing researches to use them for the drive units of EVs (electric vehicles) and e-Mobility. In this paper, the multi-objective optimization of an SWE-SM is investigated in order to improve its torque characteristics. The torque and back EMF (electromotive force) of an SWESM are calculated and analyzed using finite element simulations and Arkkio’s method considering nonlinear B-H curve of the core. In order to increase the average torque and decrease the cogging torque at the same time, the multi-objective optimization of SWE-SM is performed using the weighted sum method. Various ratios of the weighting factors of the multi-objective function are tested and the optimal solutions are analyzed to check the uniformity of the Pareto optimal points. The results show that the average torque and the cogging torque of an SWE-SM can be optimized effectively by adjusting the ratio of the weighting factors according to the preference set by the designer.

Comparative Analysis of Snowfall Accumulation and Gauge Undercatch Correction Factors from Diverse Data Sets: In Situ, Satellite, and Reanalysis

Milad Panahi,Ali Behrangi 한국기상학회 2020 Asia-Pacific Journal of Atmospheric Sciences Vol.56 No.4

Despite its importance for hydrology and water resources, accurate estimation of snowfall rate over snow-covered regions has remained a major observational challenge from both in-situ and remote sensing instruments. Snowfall accumulation can be measured by either accumulating snowfall estimates or measuring snowpack properties such as Snow Water Equivalent (SWE) and mass. By focusing on snowfall over snow accumulation period and using case studies and long-term average (2003 to 2015) over CONUS, this study compares snowfall accumulation from gauge stations (using GPCC and PRISM products), satellite products (GPCP and the suite of IMERG products), and reanalysis (ERA-interim, ERA5, and MERRA-2). Changes in SWE based on the recent UA-SWE product together with mass change observation from GRACE were used for assessment of precipitation products.We also investigated two popular gauge undercatch correction factors (CFs) used to mitigate precipitation undercatch in GPCC and GPCP. The results show that snow accumulation from most of the products is bounded by GPCC with and without correction, highlighting the critical importance of selecting proper CFs for gauge-undercatch correction. The CF based on Legates and Willmott method was found to be more consistent with the SWE-based analysis than CF based on the Fuchs method. Reanalysis show very similar spatial pattern among themselves, but represent large variation in simulating snow accumulation, with ERA-interim showing the least accumulation and MERRA-2 showing the highest accumulation and closest to the snow accumulation suggested by SWE.

GeoSensor의 공간연산을 확장한 Spatial-Sensor Observation Service

이혁(Hyuk Lee),이연(Yeon Lee),정원일(Weon-Il Chung),배해영(Hae-Young Bae) 한국컴퓨터정보학회 2011 韓國컴퓨터情報學會論文誌 Vol.16 No.11

과학과 기술의 발전은 우리의 삶에서 다양한 변화를 만들고 있다. 특히 센서는 다양한 분야에서 실시간 모니터링과 효율적인 주변 환경 분석을 위해 사용되고 있다. 그러나 기존의 센서 네트워크는 조직별 자체 정의된 프로토콜과 아키텍처를 사용함으로써 네트워크 간의 통신에 추가적인 비용을 발생시켰다. 표준화된 센서 네트워크의 부재로 인한 단점을 해결하고자 OGC에서는 표준화된 센서 및 센서 시스템에 대한 접근, 조작 등을 위해 2007년 SWE v1.0과 2011년 SWE v2.0을 발표했다. SWE는 다양한 하위 컴포넌트들로 구성되어 있는데 그 중 센서 데이터 획득을 위한 SOS에 대한 다양한 시도들이 이루어지고 있다. 그러나 기존의 SOS들은 GeoSensor의 공간연산을 고려하지 않기 때문에 매번 클라이언트에서 공간연산이 구현 및 실행됨으로써 적은 리소스를 갖는 클라이언트에 많은 부하를 초래하고 SOS의 용이성이 떨어지는 문제점이 있다. 본 논문에서는 고정 및 이동형 GeoSensor을 위한 spatialFilter와 spatialFinder 공간 연산을 확장한 S-SOS를 제안한다. 제안된 S-SOS를 사용하여 기존의 기구축된 SOS를 수정하지 않고 필요에 의해 최소한의 추가로 공간 연산을 지원할 수 있는 아키텍처를 지원하며 이에 필요한 공간 연산의 질의 표현을 설명한다. 따라서 S-SOS는 다양한 위치기반 서비스에 효과적으로 사용될 수 있음을 보인다. Advances in science and technology have made a lot of changes in our life. Especially, sensors have used in various ways to monitor in real time and analyze the world effectively. Traditional sensor networks, however, have used their own protocols and architecture so it had to be paid a lot of additional cost. In the past 8 years, OGC and ISO have been formulating standards and protocols for the geospatial Sensor Web. Although the OGC SWE initiatives have deployed some components, attempts have been made to access sensor data. All spatial operations had to calculate on the client side because traditional SOS architecture did not consider spatial operation for GeoSensor. As a result, clients have to implement and run spatial operations, and it caused a lot of overload on them and decreased approachableness. In this paper we propose S-SOS for in-situ and moving GeoSensor that extends 52 North SOS and provides spatialFilter and spatialFinder operations. The proposed S-SOS provides an architecture that does not need to edit already deployed SOSs and can add spatial operations as occasion. Additionally we explain how to express the spatial queries and to be used effectively for various location based services.

이질적인 지오센서 네트워크 데이터의 효율적인 수집 및 관리를 위한 미들웨어 시스템

김민수,이충호 대한공간정보학회 2012 Spatial Information Research Vol.20 No.1

Recently, there has been much interest in the middleware that can smoothly acquire and analyze Geosensor information which includes sensor readings, location, and its surrounding spatial information. In relation to development of the middleware, researchers have proposed various algorithms for energy-efficient information filtering in Geosensor networks and have proposed Geosensor web technologies which can efficiently mash up sensor readings with spatial information on the web, also. The filtering algorithms and Geosensor Web technologies have contributions on energy-efficiency and OpenAPI, however the algorithms and technologies could not support easy and rapid development of u-GIS applications that need various Geosensor networks. Therefore, we propose a new Geosensor network middleware that can dramatically reduce the time and cost required for development of u-GIS applications that integrate heterogeneous Geosensor networks. The proposed middleware has several merits of being capable of acquiring heterogeneous Geosensor information using the standard SWE and an extended SQL, optimally performing various attribute and spatial operators, and easily integrating various Geosensor networks. Finally, we clarify our middleware’s distinguished features by developing a prototype that can monitor environmental information in realtime using spatial information and various sensor readings of temperature, humidity, illumination, imagery, and location. 최근 센싱정보와 위치정보 그리고 주변의 공간정보를 융합한 지오센서 정보를 원활하게 수집하여 분석할 수 있는 미들웨어에 대한 관심이 증가하고 있다. 이러한 미들웨어 개발과 관련하여 지오센서 네트워크 환경에서 공간-센싱정보의 에너지 효율적인 수집을 위한 다양한 방법들이 제안되었으며, 웹에서 공간-센싱정보를 효율적으로 매쉬업 할 수 있는 Geosensor Web 기술도 제안되었다. 공간-센싱정보 수집 방법과 Geosensor Web 기술은 단일 지오센서 네트워크에서의 에너지 효율성과 OpenAPI의 제공에서 기여가 있었으나, 다양한 지오센서 네트워크와 물리적 연결을 필요로 하는 u-GIS 응용시스템의 쉽고 빠른 개발을 지원할 수는 없었다. 이에 본 논문에서는 이질적인 지오센서 네트워크들을 연계하는 u-GIS 시스템의 개발 과정에서 소요되는 시간 및 비용을 크게 감소시킬 수 있는 지오센서 네트워크 미들웨어를 제안하고자 한다. 제안된 미들웨어는 SWE와 확장 SQL 인터페이스를 이용하여 이질적인 지오센서 정보를 수집할 수 있고, 다양한 비교 및 공간 연산을 서버와 In-network 사이에서 최적화하여 수행할 수 있고, 다양한 유형의 센서 네트워크와의 쉽고 빠른 물리적 연결을 지원할 수 있는 장점을 가지고 있다. 끝으로, 온도, 습도, 조도, 속도, 영상, 위치 정보를 수집하는 지오센서를 동시에 연결하고 공간정보와 융합하여 환경정보를 실시간 감시할 수 있는 Prototype을 개발함으로써 제안된 미들웨어의 효용성을 검증하고자 한다.

Prediction of Esophageal Varices Using Non-Invasive Methods: Including Liver Stiffness by Two-Dimensional Shear Wave Elastography

( Hae Won Yoo ),( Young Seok Kim ),( Sang Gyune Kim ),( Jeongju Yoo ),( Jae Woo Park ),( Yong Seok Lim ),( Gab Jin Cheon ),( Jae Young Jang ),( Young Don Kim ),( Soung Won Jeong ),( Sae Hwan Lee ),( B 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: The Baveno VI guidelines proposed that esophagogastroduodendoscopy(EGD) for screening esophageal varices(EV) can be avoided if liver stiffness(LS) measured by transient elastography(TE) is less than 20 kPa and platelet count is greater than 150,000 cells/μL. However while validation of TE is well proven, 2D-SWE has not been sufficiently validated for EV prediction. The aim of this study is to predict the presence of EV by non-invasive tools combined with 2D-SWE and to compare the diagnostic capabilities with TE. Methods: Between January 2015 and October 2017, 258 patients with compensated advanced chronic liver disease(cACLD) who underwent 2D-SWE and EGD consecutively were enrolled. The AUROC was calculated to evaluate the accuracy of the prediction for the presence of EV using 2D-SWE, model combining 2D-SWE and platelet count(PC), liver stiffness to spleen/platelet score (LSPS) score and platelet-spleen ratio (PSR) score. 177 patients who underwent simultaneous TE examination were on the subgroup analysis was done. Results: The mean age was 56.8±10.7 years and most common etiology was chronic hepatitis B (45.0%). 83.1% of patients were in Child class A. Prevalence of all-size varices was 41.1%. 2D-SWE alone has good ability to discriminate varices (AUROCs : 0.750, 95% CI, 0.690 to 0.809). Model combining 2D-SWE with platelet count and LSPS using 2D-SWE has better discriminative ability for varices and AUROCs were 0.793 (95% CI, 0.738 to 0.848) and 0.813 (95% CI, 0.760 to 0.865) respectively. For 177 patients who performed TE and 2D-SWE simultaneously, there was no difference in predictive abilities when other factors such as albumin, bilirubin, ALT, Platelet count, hemoglobin, spleen diameter were adjusted in multivariate analysis. Conclusions: 2D-SWE combined with platelet count and LSPS seemed to be useful to predict EV. In addition, 2D-SWE has similar diagnostic performance with TE for predicting presence of EV.

The Validity of Two-dimensional Shear Wave Ultrasound (GE Elastography) for Assessing Fibrosis Stage in Patients with Chronic Liver Disease

( Sang Gyune Kim ),( Jeong Joo Yoo ),( Young Seok Kim ),( Bora Lee ),( Soung Won Jeong ),( Jae Young Jang ),( Sae Hwan Lee ),( Hong Soo Kim ),( Young Don Kim ),( Gab Jin Cheon ),( Boo Sung Kim ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Several real-time two-dimensional shear wave elastography (2D-SWE) have been developed to assess liver fibrosis with readily use of combining elastography and traditional ultrasound imaging. However, compared with transient elastography (fibroscan), the diagnostic accuracy and clinical usefulness of these methods were not fully validated. In this study, newly developed 2D-SWE (LOGIQ E9, GE healthcare, UK) was evaluated for predicting liver fibrosis stage and compared with fibroscan. Methods: Out of 1,395 patients who received 2D-SWE during May 2015 to Apr 2016, seventy (5.0%) who failed to get available value of 2D-SWE due to obesity and 131 (9.4%) with high value of AST or ALT were excluded in the analysis. Liver biopsy was performed in 177 patients. 2D-SWE measurement was considered valid when homogenous color pattern in a region of interest of at least 10 mm was shown at 10 different sites. Diagnostic performance was calculated using area under the receiver operating characteristics curve (AUROC). Results: Patients were male predominant (60.8%), their mean age was 50.4±12.4 years old and most common etiology of liver disease was hepatitis B (40.3%) followed by alcohol (26.1%). Liver fibrosis stage consisted of F0 (14.1%), F1 (12.4%), F2 (28.8%), F3 (18.1%) and F4 (26.6%). Overall, 2D-SWE was well correlated with transient elastography (r=0.788, P<0.001). 2D-SWE median values (kPa) increased with increasing stage of liver fibrosis [ F0 (5.0±1.5), F1 (6.4±2.3), F2 (6.5±2.0), F3 (9.0±2.7), F4 (12.7±2.9)] (p for trend <0.001). For the diagnosis of liver cirrhosis, AUROCs and optimal cutoff of 2D-SWE were 0.928 (95% confidence interval [CI], 0.890-0.967) and 10.1 kPa. The sensitivity, specificity, positive predictive value and negative predictive value for predicting cirrhosis were 82.2%, 92.2%, 78.7% and 93.7% respectively. For diagnosing significant liver fibrosis (≥F2), AUROCs and optimal cutoff of 2D-SWE were 0.913 (95% CI, 0.870-0.956) and 7.99 kPa. Conclusions: With effective comparability to fibroscan and availability of a conventional ultrasound examination, 2D-SWE is an useful tool for stratifying liver fibrosis stage and diagnosing liver cirrhosis.

瀟灑園 初期 詩壇의 漢詩 一考

정광휘(Kwang-hwe Jeong) 동양한문학회(구 부산한문학회) 2011 동양한문학연구 Vol.33 No.-

私家園林이면서도 湖南詩壇의 중요한 위치를 차지하고 있는 소쇄원은 한국의 전통적인 원림이다. 소쇄원은 ‘修學의 공간’이고 ‘遊戱의 공간’이며, ‘사색의 공간’이면서도 ‘迎客이나 送客의 공간’이다. 소쇄원은 호남의 격조높은 文士들이 세상물정을 잊어버리고 文雅한 마음의 즐거움을 만끽했던 별서명원(別墅名園)이기도 하다. 소쇄원에서는 수많은 문인들이 문학작품을 지었는데, 이러한 작품들은 조선 중기에서 후기까지의 소쇄원의 문화를 탐지할 수 있는 자료를 제공해 주었다. 또한 이러한 작품들은 『瀟灑園事實』에 기록되어, 호남시단의 문화를 연구하는 기본적인 자료가 되고 있다. 소쇄원에 대한 문학적 논의는 기존에 많이 진행되었다. 하지만 소쇄원의 초기 작품에 대한 연구는 여전히 미흡한 실정이다. 이에 본고에서는 소쇄원 초기 시단의 작품을 통해 초기 시단 문인들이 소쇄원에서 이룬 삶의 모습과 소쇄원은 그들에게 어떠한 의미를 부여하고 있었는지를 살피고자 한다. The So swe won Garden is private garden and Korean classical garden. It have activity of square, as study, game, think, meet a visitor and see a visitor out. At that, classical scholar leaves one's troubled times and writers image of poetry. At the garden, many of writers leaved literary works, through the works, we can know the So swe won Garden's culture in the middle and late of the Joseon Dynasty. As well the works recorded in the book of the 『So swe won Sa Seel (소쇄원사실)』. It is the basic reference of Ho nam poetical circles's culture. At before, It have no the So swe won Garden's first poetical circle's research, so writer want to research that the So swe won Garden's first poetical circle's member's mind of the first So swe won Garden and something of your.

Recovery of hesperidin and narirutin from waste Citrus unshiu peel using subcritical water extraction aided by pulsed electric field treatment

황희정,김희주,고민정,정명수 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.2

The objective of this study was to identify whether the efficacy of extracting hesperidin and narirutin from Citrus unshiu peel by-products can be increased by combining pulsed electric field (PEF) and subcritical water extraction (SWE). The samples were treated with a PEF at a strength of 3 kV/cm for 60 and 120 s. Subsequent SWE was conducted at extraction temperatures of 110–190 °C for 3–15 min. The concentration of hesperidin was highest at 46.96 ± 3.37 mg/g peel (dry basis) after PEF treatment at 120 s, combined with SWE at 150 °C for 15 min, while that of narirutin peaked at 8.76 ± 0.83 mg/g after PEF treatment at 120 s, integrated with SWE at 190 °C for 5 min. The concentrations of both hesperidin and narirutin increased with PEF treatment time. The PEF increased the amounts of hesperidin and narirutin extracted by 22.1% and 33.6%, respectively. This study demonstrate the potential of PEF pretreatment for enhancing the SWE of flavonoids from C. unshiu peel.

아임계수를 이용한 사과 과피 플라보노이드의 효율적 추출 및 항산화 활성 평가

최찬익 ( Chan Ick Cheigh ),유서연 ( Seo Yeon Yoo ),정명수 ( Myong Soo Chung ) 한국식품영양학회 2011 韓國食品營養學會誌 Vol.24 No.3

The effect of subcritical water for the extraction of total polyphenols and flavonoids from apple peel was investigated, and then the antioxidant activity of the extracts was estimated. Maximum yields of total polyphenolic compounds(36.4±1.9 mg quercetin equivalent(QE)/g dried material) and flavonoids(9.9±0.8 ㎎ QE/g dried material) were obtained by subcritical water extraction(SWE) with operating conditions of 190℃, 1,300 psi, and 20 min. Furthermore, the highest antioxidant activity(76.1±1.1%) was observed in the extract obtained from SWE using the same conditions. The flavonoids from the SWE of apple peel were compared to three conventional extraction methods in terms of their extraction efficiency and antioxidant activity. The SWE was significantly more effective than hot water (90℃), methanol, and ethanol extraction for flavonoid yield by 4.7-, 2.2-, and 1.3-fold, respectively, and for antioxidant activity by 11.0-, 4.9, and 2.8-fold, respectively.

Enhanced extraction of flavanones hesperidin and narirutin from Citrus unshiu peel using subcritical water

Cheigh, C.I.,Chung, E.Y.,Chung, M.S. Applied Science Publishers 2012 Journal of food engineering Vol.110 No.3

Flavanones including hesperidin and narirutin constitute the majority of the flavonoids that occur naturally in citrus fruits. The main purpose of this study was to extract valuable natural flavanones from agricultural by-products such as citrus peels using subcritical water extraction (SWE). Thus, the application of SWE to extraction of flavanones hesperidin and narirutin from Citrus unshiu peel was evaluated, and the effect of key operating conditions was determined by varying the extraction temperature (110-200<SUP>o</SUP>C) and time (5-20min) under high pressure (100+/-10atm). The maximum yields of hesperidin (72+/-5mg/g C. unshiu peel) and narirutin (11.7+/-0.8mg/g C. unshiu peel) were obtained at an extraction temperature of 160<SUP>o</SUP>C for an extraction time of only 10min. These yields accounted for approximately 99% of the total amount of these flavanones in the original material. The SWE was compared with three conventional extraction methods in terms of the extraction time and recovery yields for hesperidin and narirutin. The hesperidin yield by SWE was more than 1.9-, 3.2-, and 34.2-fold higher than those obtained by extraction methods using ethanol, methanol, or hot water, respectively, and the narirutin yield was more than 1.2-, 1.5-, and 3.7-fold higher.