• 제목/요약/키워드: Usefulness index

검색결과 378건 처리시간 0.025초

전력계통의 안정화를 위한 퍼지제어의 적용 (Application of Fuzzy Control for Power System Stabilization)

  • 정형환;이준탁;정동일;주석민;김해재;이광우
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 A
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    • pp.109-111
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    • 1993
  • This paper proposed a regulation technique of scale factors on fuzzy controller for power system stabilization. These scale factors arc regulated by a given exponential function with performance index variables. Simulation results show that the proposed fuzzy control technique are more powerful than conventional ones in faces of usefulness and robustness.

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Hybrid PSO를 이용한 안전도를 고려한 경제급전 (The Security Constrained Economic Dispatch with Line Flow Constraints using the Hybrid PSO Algorithm)

  • 장세환;김진호;박종배;박준호
    • 전기학회논문지
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    • 제57권8호
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    • pp.1334-1341
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    • 2008
  • This paper introduces an approach of Hybrid Particle Swarm Optimization(HPSO) for a security-constrained economic dispatch(SCED) with line flow constraints. To reduce a early convergence effect of PSO algorithm, we proposed HPSO algorithm considering a mutation characteristic of Genetic Algorithm(GA). In power system, for considering N-1 line contingency, we have chosen critical line contingency through a process of Screening and Selection based on PI(performance Index). To prove the ability of the proposed HPSO in solving nonlinear optimization problems, SCED problems with nonconvex solution spaces are considered and solved with three different approach(Conventional GA, PSO, HPSO). We have applied to IEEE 118 bus system for verifying a usefulness of the proposed algorithm.

동적 타액선 신티그라피에서 기능적 매개변수 지표를 활용한 정량 분석의 유용성 (Usefulness of the quantitative analysis by using the functional parameter index from dynamic salivary glands scintigraphy)

  • 신채호;김봉수;조용귀;조진우;진성은;표성재
    • 핵의학기술
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    • 제19권2호
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    • pp.81-86
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    • 2015
  • 동적 타액선 신티그라피는 비침습적인 방법으로 타액선의 기능을 평가하는데 널리 사용되어 왔다. 본 연구에서는 타액선 신티그라피의 시간-방사능 곡선에서 다양한 기능적 매개변수지표를 측정하고 구강건조증 환자 그룹과 건강한 Control 그룹과 비교를 통해 유용성을 알아보고자 한다. 2014년 12월부터 2015년 2월까지 구강 건조증으로 내원하여 동적 타액선 신티그라피를 시행한 환자 그룹 30명과 건강한 Control 그룹 10명을 대상으로 하였다. 검사방법은 370 MBq의 $^{99m}Tc$-과산화테크네슘을 정맥으로 순간 주사 후 약 30분간 동적 타액선 신티그라피를 연속 촬영하였으며, 주사 후 20분째에 최타 자극제로 비타민C 파우더를 이용하였다. 정량분석은 이하선과 악하선의 시간-방사능 곡선을 통해 기능적 매개변수 지표를 획득하고, 통계 프로그램을 이용하여 구강 건조증 환자와 건강한 Control 그룹과 비교하였다. 동적 타액선 신티그라피에서 이하선과 악하선의 기능적 매개변수 지표인 섭취율(Uptake Ratio, UR), 최대 방사능 시간(Time at Maximum counts, Tmax), 최소 방사능 시간(Time at Minimum counts, Tmin), 최대 축적율(Maximum Accumulation, MA), 축적속도(Accumulation Velocity), 최대 배출율(Maximum Secretion, MS), 최대 자극 배출율(Maximum Stimulation Secretion, MSS), 배출속도(Secretion Velocity, SV)를 각각 측정하였다. 구강 건조증 환자와 건강한 Control 그룹간의 이하선과 악하선의 기능적 매개변수 지표 비교에서는 최소 방사능 시간을 제외한 모든 지표에서 건강한 Control 그룹이 환자 그룹에 비하여 유의성 있게 높게 측정되었으며, 시간에 따른 변화량도 Control 그룹이 환자 그룹에 비하여 유의성 있게 변화량이 크게 측정 되었다. 동적 타액선 신티그라피에서 다양한 기능적 매개변수 지표를 이용한 정량분석은 구강 건조증 환자의 타액선 기능을 평가하는데 객관적이고 표준화된 정보를 제공해 줄 것으로 사료된다.

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R&D지출의 효율성 측면에서 특허를 이용한 KPI 개발: 특허효율성지표(PEI: Patent Efficiency Index) (Development of Key Performance Index(KPI) for R&D expenditure activities focusing on efficiency of patent)

  • 이준호;하석태;배병한;유시몬;김대성;한민현
    • 기술혁신연구
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    • 제20권3호
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    • pp.29-55
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    • 2012
  • 본 연구는 BSC의 성공적 구축과 활용에 있어 최근 변화하는 경영환경에 적절하게 대응하고, 기업의 경영활동에서 비재무적 요소가 차지하는 중요성을 감안하여 무형적 자원의 대표적 요소인 R&D 지출과 관련하여 BSC의 KPI를 개발하고, 개발된 지표의 효용성을 실증분석을 통해 검정하고자 하였다. 본 연구를 통해 BSC의 KPI로써 개발된 PEI(Patent Efficiency Index)는 R&D 지출과 R&D의 output 개념인 특허와의 상관성을 고려하여 특허의 효율성 측면에서 만들어 졌으며, 기존의 R&D관련 KPI가 가진 문제점을 해결하고, R&D 성과측정에 관한 새로운 KPI개발을 시도하였다는 점에서 연구적 의의가 있다고 하겠다. 또한 지표의 효용성에 대한 실증분석 결과, 논문의 관심변수인 PEI는 종속변수인 기업경영성과의 대용치로 나타내어진 ROA(총자산이익률)과 토빈Q에 각각 유의한 양의 영향을 미치는 것으로 나타났으며 그동안 기존 연구들에서 많은 관심을 가져왔던 R&D 지출보다 R&D의 성과측정지표로서의 설명력이 더 높은 것으로 나타났다. 이상 결과를 통해 개발된 PEI는 기존의 R&D 지출이 기업성과에 미치는 영향을 설명하는데 있어 설명하지 못하는 추가적인 설명력을 가진다고 할 수 있다. 나아가 이 지표를 통해 기업이 얼마나 효율적인 R&D 활동을 하고 있는지 알 수 있으며, 이는 기업의 R&D 활동의 효율성이 높을 때 기업의 가치나 성과가 높아진다는 것을 시사한다. 본 연구는 기업의 R&D 지출과 기업경영성과 간의 관련성을 특허와 R&D 지출의 효율적인 측면을 측정한 PEI를 통하여 직접적으로 입증함으로써 기존의 R&D 비용 외에 기업의 기업경영성과를 가늠하고 판단할 수 있는 중요한 지표로 쓰일 수 있다는 것을 규명할 수 있을 것으로 기대된다.

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한국여성의 골밀도와 운동과의 관계 (The Relationship of Exercise to Bone Mineral Density of Korean Women in Taegu)

  • 이희자
    • Journal of Nutrition and Health
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    • 제29권7호
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    • pp.806-820
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    • 1996
  • The relationship between exercise and hone mineral density (BMD) was investigated in 153 healthy women. The BMD of lumbar spine, femur(neck, ward's triangle, trochanter) and total body was determined by dual energy X-ray absorptiometry in a group subjects(65) aged 19-59 years who had been exercising(swimming or aerobic dancing) regularly for at least 2 years as well as in a similar group of nonexercising control subjects(88). Weight, height, total lean body mass(=weight-total fat body mass-bone mineral content), animal and meat Ca, Ca index, energy expenditure, BMD, PYD/Cr were significantly higher in the exercisers than the controls. There were significantly negative correlations between age, ALP and osteocalcin and BMD, but significantly positive correlations between weight, BMI, total fat body mass and total lean body mass and BMD. Stepwise multiple regression analysis revealed that total lean body mass may be a better independent predictor to BMD than total fat body mass. The nutrient intakes were more closely related to BMD in the exercisers than the controls, but energy expenditure was more closely related to BMD in the controls than the exercisers Stepwise multiple regression analysis revealed that BMD was closely related to menopause, osteocalcin, age, weight in both groups but energy intake in the exercisers alone, energy expenditure in control alone. In premenopausal women, the exercisers had significantly greater BMD than the controls. But, in postmenopausal women, no significant difference between two groups was detected. When compared to BMD of the subjects with same age range to minimize the effect of age, aerobic dancing appears to be capable of exerting a positive effect on BMD in a group of subjects aged 19-44. However, no relationship of the swimming to BMD could be identified in a group of subjects aged 37-59. The results of this study suggest that the usefulness of exercisng appears to be significantly greater in preemenopausal women than postmenoparusal women and weight bearing activity, aerobic dancing is associated with increasing BMD at the weight bearing sites and could be beneficial in the prevention of bone loss. But the usefulness of swimming on bone should be further investgated.

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M-test에 근거한 만성 경항통 환자의 진단 및 치료: 전후비교 임상연구 (Clinical Usefulness of M-test on Patients with Chronic Neck Pain: A Single Arm Pre-post Comparison Study)

  • 조우영;정석희
    • 한방재활의학과학회지
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    • 제26권4호
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    • pp.67-75
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    • 2016
  • Objectives The purpose of this study was to investigate the clinical usefulness of M-test (Meridian test) as an adjunctive evaluation and treatment in patients with chronic neck pain. Methods This study was a single arm pre-post comparison study. Thirty-six eligible subjects with chronic neck pain were recruited from August to September, 2015. M-test was used for evaluating the condition of meridian, which can induce the limitation of ROM and body discomfort. Subjects were offered intradermal acupuncture treatment on one-acupoint for 48 hours. Cervical numeric rating scale (NRS), cervical range of motion (ROM), neck disability index (NDI) and surface electromyography (SEMG) were measured before and after the treatment. Total NRS and the number of movement limitation of M-test were also measured before and after the treatment. Results Among the 36 participating subjects, 4 subjects were lost to follow-up or excluded in accordance with the criteria. Significant differences on Cervical NRS and NDI were found after the treatment (p<0.001). There was a significant difference in the range of left cervical rotation (p<0.05). Root mean square (RMS) of SEMG significantly decreased on the right sternocleidomastoid muscle (p<0.05), but significantly increased on the right trapezius muscle (p<0.05). Median frequency (MdF) of SEMG significantly increased on both sternocleidomastoid muscles. There appears to be significant differences after the treatment in total NRS and the number of movement limitation of M-test (p<0.05). Conclusions These results suggest that the evaluation and treatment of M-test based on the meridian and collateral theory were effective on cervical NRS and NDI, and also improved the movability of human body.

Antioxidative Properties of Brown Algae Polyphenolics and Their Perspectives as Chemopreventive Agents Against Vascular Risk Factors

  • Kang, Keejung;Park, Yongju;Hwang, Hye-Jeong;Kim, Seong-Ho;Lee, Jeong-Gu;Shin, Hyeon-Cheol
    • Archives of Pharmacal Research
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    • 제26권4호
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    • pp.286-293
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    • 2003
  • Several polyphenolic compounds and complex mixtures were isolated from brown algae species. The 1,1-diphenyl-2-picryhydarzyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) of these compounds were evaluated to determine their physiological usefulness as antioxidants for vascular protection. The antioxidative protection of low-density lipoprotein (LDL) was also evaluated and compared with that of catechin, because the generation of oxidized LDL is one of the most active and specific risk factors contributing to atherogenesis. Oral administration to rats of a commercially available sample ($VNP^{TM}$) containing 30% of these polyphenolic compounds and 70% dietary fiber revealed that the serum reducing capacity measured in terms of FRAP value was significantly elevated 30 min after the treatment, but declined rather quickly thereafter, indicating the good oral absorption of the compounds and their fast binding to the lumenal surface of the blood vessels. An eight-week, human, clinical trial (n=31) of $VNP^{TM}$ showed significant improvement in erectile function measured by IIEF (international index of erectile function) score. These results collectively demonstrated the usefulness of these polyphenolic compounds as fundamental chemopreventive agents against vascular risk factors originating from oxidative stress.

Usefulness of Oblique Lateral Interbody Fusion at L5-S1 Level Compared to Transforaminal Lumbar Interbody Fusion

  • Mun, Hah Yong;Ko, Myeong Jin;Kim, Young Baeg;Park, Seung Won
    • Journal of Korean Neurosurgical Society
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    • 제63권6호
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    • pp.723-729
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    • 2020
  • Objective : The use of oblique lateral interbody fusion at the L5-S1 level (OLIF51) is increasing, but no study has directly compared OLIF51 and transforaminal lumbar interbody fusion (TLIF) at the L5-S1 level. We evaluated the usefulness of OLIF51 by comparing clinical and radiologic outcomes with those of TLIF at the same L5-S1 level. Methods : We retrospectively reviewed and compared 74 patients who underwent OLIF51 (OLIF51 group) and 74 who underwent TLIF at the L5-S1 level (TLIF51 group). Clinical outcomes were assessed with the visual analogue scale for back pain and leg pain and the Oswestry Disability Index. Mean disc height (MDH), foraminal height (FH), disc angle (DA), fusion rate, and subsidence rate were measured for radiologic outcomes. Results : The OLIF51 group used significantly higher, wider, and larger-angled cages than the TLIF51 group (p<0.001). The postoperative MDH and FH were significantly greater in the OLIF51 group than in the TLIF51 group (p<0.001). The postoperative DA was significantly larger in the OLIF51 group than in the TLIF51 group by more than 10º (p<0.001). The fusion rate was 81.1% and 87.8% at postoperative 6 months in the OLIF51 and TLIF51 groups, respectively, and the TLIF51 group showed a higher fusion rate (p<0.05). The subsidence rate was 16.2% and 25.3% in the OLIF51 and TLIF51 groups, respectively, and the OLIF51 group showed a lower subsidence rate (p<0.05). Conclusion : OLIF51 was more effective for the indirect decompression of foraminal stenosis, providing strong mechanical support with a larger cage, and making a greater lordotic angle with a high-angle cage than with TLIF.

뇌졸중 환자 및 보호자의 건강신념이 재활치료 이행 및 일상생활동작 수행능력에 미치는 영향 (Health beliefs of patients and caregivers of stroke rehabilitation in the implementation and impact the ability to perform everyday actions)

  • 이연섭;문병무
    • 대한물리치료과학회지
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    • 제18권4호
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    • pp.11-18
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    • 2011
  • Purpose : This study attempts to assist stroke patients lead independent daily life movements by providing basic data for stroke patients' successful rehabilitation program and understanding the relationship between health beliefs of stroke patients and their guardians, and patients' rehabilitation performance level and daily life movement fulfillment ability. Methods : 23 stroke patients receiving treatments at rehabilitation specializing hospital after getting diagnosed with a stroke, along with 23 guardians were selected as research subjects, and health belief was measured by modifying supplementing Byun Young-Hee(2002)'s health belief measurement tool for leg movement disorder patients. Research findings revealed the following relationship between health beliefs of stroke patients and their guardians, and patients' rehabilitation performance and daily life movement fulfillment ability. Results : The patients group's initial MBI score was $33.13{\pm}3.46$, and measurement after four weeks was $38.43{\pm}3.47$. As health beliefs got stronger, MBI score increased significantly(p<.05). Correlation analyses of factors that affect rehabilitation attendance rate showed that perceived susceptibility, seriousness and usefulness were statistically significant, and perceived disability was not statistically significant(p<.05). Guardians' health belief index(susceptibility, seriousness, usefulness, disability) had no correlation with rehabilitation attendance rate. Conclusion : In order to increase daily life movement fulfillment ability of patients who are being treated with stroke, health beliefs must be raised to increase changes in daily life movement fulfillment ability. Therefore, it is believed that managing programs that can increase health beliefs of stroke patients can allow patients obtain positive health beliefs, further increase rehabilitation performance rate of stroke patients as well as independent daily life ability.

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지역사회 획득 폐렴환자의 중증도 평가에서 혈청 코티졸의 유용성 (Usefulness of Serum Cortisol in Assessment for the Severity of Community-Acquired Pneumonia)

  • 윤경화;김연재;김미영;김은영;배명남;배상묵;김민수;박훈표
    • Tuberculosis and Respiratory Diseases
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    • 제69권6호
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    • pp.450-455
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    • 2010
  • Background: High cortisol levels are frequently observed in patients with severe infections are of prognostic value in sepsis. The aim of this study was to evaluate the clinical usefulness of serum cortisol in assessment for the severity of community-acquired pneumonia (CAP). Methods: This study analyzed the results of 52 CAP subjects admitted in Changwon Fatima Hospital between July 2008 to May 2010. Total serum cortisol, infection markers such as C-reactive protein (CRP), procalcitonin (PCT) and CURB (Confusion, Uremia, Respiratory rate, Blood pressure)-65 were examined retrospectively. Results: In clinically unstable subjects on admission day 4, baseline serum cortisol, CURB-65, and CRP were elevated significantly compared to those of stable subjects. Area under curve (AUC) of cortisol, CRP, and CURB-65 from ROC curves were 0.847, 0.783, and 0.724 respectively. In the subjects with serum cortisol ${\geq}22.82{\mu}g/dL$, CRP, PCT, CURB-65 score, and mortality were significantly elevated. Conclusion: These findings suggest that measurement of serum cortisol in early stage may provide helpful information in the assessment of CAP severity.