Design and Implementation of Solar PV for Power Quality Enhancement in Three-Phase Four-Wire Distribution System

Guna Sekar, T,Anita, R 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.1

This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

Which Users Should Be the Focus of Mobile Personal Health Records? Analysis of User Characteristics Influencing Usage of a Tethered Mobile Personal Health Record

Lee, Guna,Park, Joong Yeol,Shin, Soo-Yong,Hwang, Jong Su,Ryu, Hyeon Jeong,Lee, Jae Ho,Bates, David W. Mary Ann Liebert, Inc. 2016 TELEMEDICINE JOURNAL AND E HEALTH Vol.22 No.5

<P><B>Abstract</B></P><P><B><I>Background:</I></B><I>This study was conducted to analyze the usage pattern of a hospital-tethered mobile personal health records (m-PHRs) application named My Chart in My Hand (MCMH) and to identify user characteristics that influence m-PHR usage.</I><B><I>Materials and Methods:</I></B><I>Access logs to MCMH and its menus were collected for a total of 18 months, from August 2011 to January 2013. Usage patterns between users without a patient identification number (ID) and users with a patient ID were compared. Users with a patient ID were divided into light and heavy user groups by the median number of monthly access. Multiple linear regression models were used to assess MCMH usage pattern by characteristics of MCMH user with a patient ID.</I><B><I>Results:</I></B><I>The total number of MCMH logins was 105,603, and the median number of accesses was 15 times. Users (</I>n<I> = 7,096) mostly accessed the “My Chart” menu, but “OPD [outpatient department] Service Support” and “Health Management” menus were also frequently used. Patients with chronic diseases, experience of hospital visits including emergency room and OPD, and age group of 0–19 years were more frequently found among users with a patient ID (</I>n<I> = 2,186) (</I>p <I>< 0.001). A similar trend was found in the heavy user group (</I>n<I> = 1,123). Submenus of laboratory result, online appointment, and medication lists that were accessed mostly by users with a patient ID were associated with OPD visit and chronic diseases.</I><B><I>Conclusions:</I></B><I>This study showed that focuses on patients with chronic disease and more hospital visits and empowerment functions in a tethered m-PHR would be helpful to pursue the extensive</I><I>use.</I></P>

RFID 애플리케이션 프레임워크 기반의 학생 출결 관리 시스템

김건아(Guna Kim),정목동(Mokdong Chung) 한국멀티미디어학회 2008 한국멀티미디어학회 학술발표논문집 Vol.2008 No.2

출결관리시스템은 RFID 애플리케이션 개발환경을 지원하기 위하여 본 연구실에서 개발한 EAF (Enterprise Application Framework)를 이용하여 강좌에 참여하는 다수의 학생들에 대한 출결관리의 업무를 수행하는 시스템이다. 강의실 출입구에 리더기를 설치하고 학생들이 소지한 RF칩이 내장된 학생증을 자동으로 인식함으로써 보다 효율적인 출결관리를 수행하고 강의시간 활용의 극대화와 반복적이고 중복된 업무 프로세스를 개선하여 교육서비스의 질적인 향상에 목표를 두고 있다.

가임기 여성의 규칙적 운동 및 운동종류에 따른 대사증후군 간의 관련성

이건아(Guna Lee) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.1

본 연구의 목적은 가임기 여성의 규칙적 운동 및 운동의 종류에 따른 대사증후군 간의 관련성을 파악하여 효과적인 대사증후군 예방 및 관리 중재 개발을 위한 기초자료를 제공하고자 한다. 본 연구는 제7기 3차년도 국민건강영양조사 원시자료(KNHANES Ⅶ-3, 2018년)를 이용하여 만 19세 이상 가임기 여성 4172명을 대상으로 시행하였으며, 규칙적 운동의 종류에 따른 대사증후군 구성요소의 차이는 복합표본 t검정으로, 규칙적 운동의 종류가 영향을 미치는 대사증후군의 유병 위험은 복합표본 다중 로지스틱 회귀분석으로 분석하였다. 가임기 여성의 대사증후군 유병률은 3.1%(128명)이었으며 가임기 여성 중 규칙적 운동 실천군은 1979명(46.5%)이었다. 가임기 여성의 규칙적 운동 실천군은 미실천군과 비교하여 다섯 가지 대사증후군 구성요소 중 수축기 혈압(p =.002), 허리둘레(p<.001)와 공복혈당(p =.007)가 상대적으로 낮았으며 고밀도콜레스테롤(p < .001)는 상대적으로 높았다. 규칙적 운동중 규칙적 근력운동 실천군은 규칙적 근력운동 미실천군과 비교하여 수축기 혈압(p < .001), 이완기 혈압(p = .005), 허리둘레(p < .001), 공복혈당(p < .001)과 중성지방(p = .015) 모두 상대적으로 낮았고 고밀도콜레스테롤(p < .001)은 상대적으로 높았다. 대사증후군에 영향을 미치는 혼란 변수들을 통제한 후, 규칙적 운동 실천군(유병교차비 0.59, 95% 신뢰구간 0.35-0.98, p = .040)과 규칙적 근력운동 실천군(유병교차비 0.34, 95% 신뢰구간 0.14-0.80, p= .013)은 각각 미실천군과 비교하여 대사증후군 유병위험이 낮게 나타났다. 그러므로 규칙적 운동은 가임기 여성의 대사증후군 유병 위험을 낮추는 중요한 변수임을 알 수 있으며, 가임기 여성의 대사증후군 예방 및 관리를 위한 운동 중재 개발 시 근력운동을 포함할 필요가 있음을 제언한다. The purpose of this study was to identify the association between regular physical activity (PA) types and metabolic syndrome (MetS) in fertile women. Data were obtained from the seventh Korea National Health and Nutrition Examination Survey (KNHANES Ⅶ-3, 2018). The sample consisted of 4,172 fertile women over 19 years of age. The data were analyzed using an independent t-test, χ2 test, and multiple logistic regression analysis for examining the association of regular PA and MetS. The prevalence of MetS in fertile women was 3.1% (n =128), and 1,972 fertile women (47.2%) practiced regular PA. Compared to the non-regular PA group, regular PA resulted in a significantly lower systolic blood pressure (p =.002), lower waist circumference (p <.001), lower fasting blood sugar (p =.007), and higher high-density lipoprotein cholesterol (p <.001). After controlling the confounding variables, multiple logistic regression showed that the regular PA group (odds ratio 0.59, 95% confidence interval 0.35-0.98, p =.040) and the regular muscle-strengthen PA group (odds ratio 0.34, 95% confidence interval 0.14-0.80, p =.013) were associated with a decreased risk of MetS. Therefore, regular PA, including muscle-strengthen PA should be considered to develop effective MetS intervention in fertile women.

A New Voxelization Strategy in Compressed-Sensing (CS)-Based Iterative CT Reconstruction for Reducing Computational Cost: Simulation and Experimental Studies

Kim, Guna,Park, Soyoung,Je, Uikyu,Cho, Hyosung,Park, Chulkyu,Kim, Kyuseok,Lim, Hyunwoo,Lee, Dongyeon,Lee, Hunwoo,Park, Yeonok,Woo, Taeho Springer-Verlag 2018 Journal of medical and biological engineering Vol.38 No.1

<P>In recent computed tomography (CT) reconstruction, iterative methods have been often used owing to the potential to provide three-dimensional (3D) images of superior reconstruction quality to common filtered-back-projection (FBP)-based methods. However, these methods require enormous computational cost in the iterative process, which has still been an obstacle to put them to practical use. In this work, to overcome these difficulties, we propose a new cone-beam CT reconstruction with a dual-resolution voxelization strategy for a small region-of-interest (ROI) reconstruction in which the voxels outside the target ROI are binned by, for example, 2 x 2 x 2, 4 x 4 x 4, 8 x 8 x 8, etc., while the other voxels remain unbinned. We considered a compressed-sensing (CS)based algorithm with a dual regularization strategy, rather than common FBP-based methods, for more accurate CT reconstruction. We implemented the proposed CS-based algorithm and performed a systematic simulation and experiment. Our results indicate that the proposed method seems to be effective for reducing computational cost considerably in iterative CT reconstruction, keeping the reconstruction quality inside the target ROI not much degraded.</P>

In Vertebral Hemangiomas with Neurological Deficit, Is a Less Extensive Approach Adequate?

K. Guna Pratheep,Shetty Ajoy Prasad,K. S. Srivijayanand,Kavishwar Rohit,Kanna Rishi Mugesh,Rajasekaran Shanmuganathan 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.1

Study Design: This was a retrospective study. Purpose: To analyze the surgical and neurological outcomes following surgical decompression in patients with aggressive vertebral hemangioma (AVH) presenting with neurological deficit and to determine whether a less extensive approach is appropriate. Overview of Literature: AVHs are a rare subset of benign vascular tumors frequently presenting with neurological deficit because of spinal cord compression. Though the results of surgical management have improved over time, there is a lack of consensus on the ideal management in this group of patients. Methods: Twenty-one patients who underwent surgery for AVH between 2009 and 2018 were analyzed. Demographic and clinical details of patients were retrieved from hospital information system. Imaging information (i.e., radiography, computed tomography, magnetic resonance imaging) of all patients was accessed and analyzed in picture archiving and communication system. Tumor staging was performed using Enneking and Weinstein–Boriani–Biagini classifications and Spinal Instability Neoplastic Score. At followup, neurological and radiological evaluations were performed. Results: Twenty-one patients (13 [61.9%] females and 8 [38.1%] males) were included with a mean age of 44.29 years (range, 14–72 years). All patients in the study had neurological deficit. Back pain was present in 80.9% of patients. Mean duration of symptoms was 4.6 months (range, 1 day to 10 months). Most common lesion location was thoracic spine (n=12), followed by thoracolumbar (D11– L2; n=7) and lumbar (n=2) regions. Ten patients had multiple level lesions. All patients underwent preoperative embolization. Nine patients underwent intralesional spondylectomy with reconstruction; another nine patients underwent stabilization, decompression, and vertebroplasty; three patients underwent decompression and stabilization. Neurology improved in all patients, and only one case of recurrence was noted in a mean follow-up of 55.78±25 months (range, 24–96 months). Conclusions: In AVH, good clinical and neurological outcomes with low recurrence rates can be achieved using less extensive procedures, such as posterior instrumented decompression with vertebroplasty and intralesional tumor resection.

우리나라 방문건강관리사업의 과거, 현재와 미래

이건아(Lee, Guna),양숙자(Yang, Sook-Ja),우은효(Woo, Eunhyo) 한국보건간호학회 2018 韓國保健看護學會誌 Vol.32 No.1

Purpose: We present improvements to the Korean home visiting healthcare service based on analysis of Korean home visiting healthcare services considering recent sociodemographic changes and demands for healthcare services. Methods: This is a review study in which the results are derived through a literature review and data analysis. We collected data through a search of electronic databases, Google Scholar, and governmental websites. Results: Changes in Korean home visiting healthcare services are classified into four stages: ‘introduction (1990–2000)’, ‘pilot project (2003-2006)’, ‘nationwide expansion (2007–2012)’, ‘various types (2013–2018)’. Korean home visiting healthcare service based on public health centers has achieved outcomes such as improved health behavior and health management, increased health management ability, and establishment of comprehensive healthcare infrastructure. Conclusion: In the future, the demand for home visiting healthcare service will increase steadily because of deepening social polarization, rapid aging of the population, and increases in chronic diseases. To improve health management and health equity, we suggest that Korean home visiting healthcare service will expand to all the people as a core public health service. It is necessary to establish a management team for various types of home visiting healthcare service in the public health center.

대사증후군에 대한 식이와 운동 효과에 대한 메타분석

이건아(Lee, Guna),최혜영(Choi, Hye-Young),양숙자(Yang, Sook-Ja) 한국간호과학회 2015 Journal of Korean Academy of Nursing Vol.45 No.4

Purpose: This study identified effects of dietary and physical activity interventions including dietary interventions or physical activity interventions alone or combined dietary-physical activity interventions to improve symptoms in metabolic syndrome including abdominal obesity, high triglycerides, low high density lipoprotein cholesterol, elevated blood pressure, and elevated fasting glucose through meta-analysis. Methods: Articles on metabolic syndrome X published from 1988 to 2013 were searched through electronic databases, Google Scholar, and reference reviews. Methodological quality was assessed by the checklist, SIGN (Scottish Intercollegiate Guidelines Network). Results: In the meta-analysis, there were 9 articles reporting 13 interventions with 736 participants. Using random effect models, the dietary and/or physical activity interventions showed a lower mean difference in waist circumference ( - 1.30 cm, 95% CI: - 2.44~ - 0.15, p =.027). The combined dietary-physical activity interventions showed a lower mean difference in waist circumference ( - 2.77 cm, 95% CI: - 4.77~ - 0.76, p =.007) and systolic blood pressure ( - 5.44 mmHg, 95% CI: - 10.76~ - 0.12, p =.044). Additionally, interventions of over 24 weeks yielded a lower mean difference in waist circumference ( - 2.78 cm, 95% CI: - 4.69~ - 0.87, p =.004) and diastolic blood pressure ( - 1.93 mmHg, 95% CI: - 3.63~ - 0.22, p =.026). Conclusion: The findings indicate that dietary and/or physical activity interventions for metabolic syndrome reduce central obesity with no adverse effects. This finding provides objective evidences for dietary and physical activity management on metabolic syndrome as an efficient intervention.

대학교 금연캠퍼스 정책 효과에 대한 이론적 고찰

이건아 청주대학교 보건의료과학연구소 2020 보건의료과학연구 Vol.8 No.2

This study identified effects of university smoke-free policies to improve health of students, staff, and visitors and prevent tobacco use and secondhand smoke exposure through systematic review. Articles on university smoke-free policies were searched through electronic databases(PubMed & KISS), and reference reviews. In systematic review, there were 6 articles reporting 43 campuses with 8309 participants. Smoke-free campus policies included smoking bans on campus, campaigns including advertisements on an internal campus TV network and internal newspapers, providing educational materials like smoking cessation contact information, and screening students' use of tobacco. The effects of smoke-free campus policies were evaluated by secondhand smoke exposure, tobacco use(self-report survey, direct observation of violators, and cigarette butts), attitudes and beliefs related to smoking, and support for smoke-free campus. This study lends considerable support for efforts towards smoke-free campus.

Roost tree characteristics of Pteropus medius (Chiroptera: Pteropodidae) in the midland laterite hillocks of northern Kerala, India

Malik Fasil Madala,Christopher Guna,Anusree Pradeepan,Ayyoob K Chalil 국립중앙과학관 2022 Journal of Asia-Pacific Biodiversity Vol.15 No.4

The roost tree characteristics of Indian flying fox (Pteropus medius) were studied in the midland lateritehillocks of northern Kerala in peninsular India. A total of 170 trees belonging to 20 families, 32 genera,and 37 species were identified as roost trees from eleven roost sites located in Kannur and Kasargoddistricts of northern Kerala. Roost tree parameters such as habit, origin, diameter at breast height (DBH),tree height, bole height, crown length, crown spread, and crown closure were analyzed. Families Ana cardiaceae and Lamiaceae represented more number of roost trees in the study area. The mean batabundance per tree for the entire study area was found to be 54.35 5.2 and it was highest for Ficusreligiosa (peepal) followed by Tetrameles nudiflora (false hemp tree) and Leucaena leucocephala (subabul). Bats showed a preference for native trees and did not show any difference in the selection of evergreenand deciduous trees for roosting. The study also revealed that P. medius prefers large trees with greaterheight, diameter, crown length, and crown spread. As the midland laterite hillocks are under severehabitat degradation, the study recommends preserving large trees for better conservation of theremaining habitats of P. medius in the area.