• Title/Summary/Keyword: Third-difference

Search Result 3,608, Processing Time 0.026 seconds

A Study of Influences Caused by Far Infrared and Anion on Human Body (원적외선과 음이온이 인체에 미치는 효과)

  • Kim, Wan-Gyeom;Kim, Seong-Sam;You, Seung-Hyun;Kil, In-Ho;Kwon, So-Hee;Lee, Ki-Nam
    • Journal of Society of Preventive Korean Medicine
    • /
    • v.9 no.2
    • /
    • pp.93-106
    • /
    • 2005
  • A survey was performed for 2 weeks in October 2004 in order to examine the effects and changes of far infrared and anion of office workers aged 40 and older before and after wearing the underwear. In the survey, questionnaires and photoplethysmography were used to measure the difference between the two tests conducted with one week interval. The findings could be summed up as follows: 1. There was no statistically significant difference in changes of vascular aging points and photoplethysmogram wave form before and after wearing the far infrared and anion underwear but the points showed the increasing tendency(p>0.05). 2. A statistically significant difference was confirmed since the total points of each item in the questionnaires increased after wearing the underwear(p<0.001). 3. In connection with the systemic symptoms, a significant difference was found with increased points in all items except for no. 6 after wearing the underwear(p<0.05). 4. With regard to the difference before and after wearing the underwear depending on the Kidney symptoms, there was a significant difference with increased points in all items except for item no. 1 after wearing the underwear(p<0.05). In conclusion, to put on the underwear with effect of far infrared and anion is believed to smooth metabolism and blood circulation, contributing by thus to promoting health and preventing disease. Further studies with wider sampling of subjects are requested to diversify and refine the findings from this sectional study.

  • PDF

A Busbar Current Differential Relay with a Compensating Algorithm (보상 알고리즘을 적용한 모선보호용 전류차동 계전기)

  • 강용철;윤재성
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.53 no.4
    • /
    • pp.214-220
    • /
    • 2004
  • This paper describes a busbar current differential relay in conjunction with a current transformer(CT) compensating algorithm irrespective of the level of the remanent flux. The compensating algorithm detects the start of first saturation if the third-difference function of the current exceeds the threshold; it estimates the core flux at the first saturation start by inserting the negative value of the third-difference function of the current into the magnetization curve; thereafter, it calculates the core flux during the fault and compensates the distorted current using the magnetization curve. The algorithm estimates the correct secondary current irrespective of the level of the remanent flux and needs no saturation point of the magnetization curve. The proposed relay can improve not only security of the relay on an external fault with CT saturation but sensitivity of the relay on an internal fault; the relay can improve the operating speed on n internal fault with CT saturation. This paper concludes by implementing the relay into a digital signal processor based prototype relay.

Study on the Third-Order-Upwind-Difference(TOUD) for the Free-Surface Simulation (자유표면시뮬레이션의 TOUD 연구)

  • KWAG SEUNG-HYUN
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • 2004.11a
    • /
    • pp.154-159
    • /
    • 2004
  • A new finite difference scheme is studied fur the simulation of free surface, surface the third derivative tenn for the wave elevation is artificially added in the the free-surface boundary condition. This study presents a comparative analysis with simulations performed by using the classical MAC method. More systematic computations are carried out by changing the submergence depth and angle of attack. Through the numerical simulation, it is found that a new numerical method becomes more efficient for the reason that the free surface elevation is reasonably developed at tire rear of trailing edge.

  • PDF

A Busbar Current Differential Relay with a Compensating Algorithm (보상 알고리즘을 적용한 모선보호용 전류차동 계전기)

  • 강용철;윤재성
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.53 no.4
    • /
    • pp.214-214
    • /
    • 2004
  • This paper describes a busbar current differential relay in conjunction with a current transformer(CT) compensating algorithm irrespective of the level of the remanent flux. The compensating algorithm detects the start of first saturation if the third-difference function of the current exceeds the threshold; it estimates the core flux at the first saturation start by inserting the negative value of the third-difference function of the current into the magnetization curve; thereafter, it calculates the core flux during the fault and compensates the distorted current using the magnetization curve. The algorithm estimates the correct secondary current irrespective of the level of the remanent flux and needs no saturation point of the magnetization curve. The proposed relay can improve not only security of the relay on an external fault with CT saturation but sensitivity of the relay on an internal fault; the relay can improve the operating speed on n internal fault with CT saturation. This paper concludes by implementing the relay into a digital signal processor based prototype relay.

Design of a CT Saturation Detection Technique with the Countermeasure for a Spike Signal

  • Kang, Yong-Cheol;Yun, Jae-Sung
    • KIEE International Transactions on Power Engineering
    • /
    • v.3A no.2
    • /
    • pp.85-92
    • /
    • 2003
  • When a current transformer (CT) is saturated, the wave-shape of the secondary current is distorted and contains points of inflection, which correspond to the start or end of each saturation period. Discontinuity in the first-difference function of the current arises at points of inflection, where the second and third differences convert into pulses that can be used to detect saturation. This paper describes the design and evaluation of a CT saturation detection technique using the third-difference function and includes the countermeasure for a spike signal. Test results clearly demonstrate that the algorithm successfully detects the start and end of each saturation period irrespective of the remanent flux and magnetization inductance in the saturated region. This paper concludes by describing the results of hardware implementation of the algorithm using a DSP.

Parent Attachment, Peer Support and Behavior Problems of Middle School Students (중학생의 부모에 대한 애착, 친구지지와 행동문제)

  • 김인숙;이경님
    • Korean Journal of Human Ecology
    • /
    • v.7 no.2
    • /
    • pp.97-113
    • /
    • 2004
  • This study was to investigate the relationship between parent attachment, peer support and behavior problems of middle school students. The subjects were 591 male and female students in the first and third grade of the middle school and their mothers in Busan. The instruments used for this study were Inventory of Parent Attachment Scale, Peer Support Scale and Behavior Checklist for Adolescents. The results were as follows: 1. The first grade students had stronger attachment on father and mother than third grade. The third grade students had perceived peer support more than first grade. Female students had stronger attachment on mother and perceived peer support more than male students. And there was no significant sex difference in attachment on father. In the case of female students, internalizing and externalizing behavior problems increased grade. But, in the case of male students, there was no grade difference in internalizing and externalizing behavior problems. In the case of first grade students, there was no sex difference in internalizing behavior problems. In the case of first grade students, males had more externalizing behavior problems than females. But in the case of third grade students, females had more externalizing behavior problems than males. 2. As parent's education level was higher, students had stronger attachment on parents and perceived more peer support. As family income was higher, students had stronger attachment on father and perceived more peer support. 3. In case of female students, parent attachment and peer support were correlated negatively with internalizing and externalizing behavior problems. In case of male students, attachment on fathers and peer.

  • PDF

THE LOWER BOUND OF THE THIRD-ORDER INTERMODULATION PRODUCTS (3차 INTERMODULATION의 LOWER BOUND에 관한 연구)

  • Jang, Ki-Soong;Lee, Young-Choul
    • Proceedings of the KIEE Conference
    • /
    • 1987.07b
    • /
    • pp.859-863
    • /
    • 1987
  • In this paper, a relationship between difference triangular sets and sum triangular sets is developed to evaluate the weighted number of the third-order intermodulation products. In addition, a lower bound of the intermodulation products falling into the worst signal channel has been derived using the relationship between difference triangular sets and sum triangular sets. The formulas of the lower bound are useful for estimating the intermodulation impairment level in satellite communication systems.

  • PDF

EVALUATION OF ROOT CANAL TRANSPORTATION AND REMAINING DENTIN/CEMENTUM THICKNESS FOLLOWING HAND AND ULTRASONIC INSTRUMENTATION (근관형성 방법에 따른 근관변위와 잔존치질의 두께에 관한 연구)

  • Seo, Byoung-Kon;Cho, Young-Gon
    • Restorative Dentistry and Endodontics
    • /
    • v.17 no.2
    • /
    • pp.399-412
    • /
    • 1992
  • The purpose of this study was to evaluate the root canal transportation and remaining dentin / cementum thickness after using hand and ultrasonic instrumentation in the curved mesial root canals of extracted human mandibular molars. Fourty - six clear polyether blocks were made and randomly divided into two groups: hand instrumentation group with K - Flex files and ultrasonic instrumentation group with Suprasson SP unit. All root canals were instrumented to a size corresponding to a # 30 K - Flex file 1mm short from the radiographic apex. The roots were then sectioned perpendicular to the long axis so the apical and middle third could be evaluated with the Zoom stereomicroscope. The results were as follows : 1. In the total amount of removed dentin at middle third level, there was not significant difference between the hand instrumentation and ultrasonic instrumentation (P>0.05). 2. In the total amount of removed dentin at apical third level, there was more removed by the ultrasonic instrumentation than hand instrumentation(P<0.005). 3. In the transportation width, there was not significant difference between the two groups at both sectioned levels(P>0.05). 4. It was suggested that the canal was transported distally at middle third level and mesially at apical third level by booth techniques.

  • PDF

The difference of Quantitative Analysis According to the Method of Region of Interest Setting in $^{99m}Tc$-DMSA Renal Scan ($^{99m}Tc$-DMSA 신장 검사에서 ROI 설정 방법에 따른 정량분석 차이에 관한 연구)

  • Lee, Jong-Hun;Shim, Dong-Oh
    • The Korean Journal of Nuclear Medicine Technology
    • /
    • v.14 no.1
    • /
    • pp.73-77
    • /
    • 2010
  • Purpose: The nuclear medicine technology has been changed. The hard ware is developed so much. Also the soft ware performs a meritorious deed for the development of nuclear medicine technology. We could use the automated region of interest (ROI) instead of manual ROI. We want to know that what difference of quantitative analysis is there between automated ROI and manual ROI Materials and Methods: There are three experimental to make results. The first is what comparing the renal automated ROI and manual ROI. The second is that we compared three threshold ROI that size is difference each others with visible decision. The third is that we compared full, half, quarter automated background, and survey relative function. Results: Although the first has statistically not significant difference, the second and third have significant difference. Threshold, setting smaller threshold then renal outline or bigger, has statistically significant difference (p<0.01). The third is performed with the first experimental. Full background has significant difference, comparing each three type background (p<0.05). Conclusion: The results that there is not significant difference between automated ROI and manual ROI will increase objectivity and operator's convenience. We could know that smaller threshold then renal out line has significant difference in the second experimental. And the third experimental has results because of a increased background nearby live and spleen.

  • PDF

A Study on the Variation of Tensile Strength and Hardness According to the Frequency of Reuse with Chrome-Cobalt Alloy Widely used in the Production of Partial Denture (국부의치 제작에 사용되는 Chrome Cobalt Alloy의 재주조 횟수에 따른 인장강도 및 경도 변화에 대한 실험적 연구)

  • Chung, Kyung-Pung
    • Journal of Technologic Dentistry
    • /
    • v.18 no.1
    • /
    • pp.15-25
    • /
    • 1996
  • This study is to measure and compare the hardness and tensile strength of each time after we recast seven times continually only with and metal alloy Chromium-Cobalt alloy used in the production of partial denture frame work. The result of the experiment were as follow; 1) The result of the hardness measurement The result of the first casting was $490.48{\pm}38.38$ and that of the second recasting was $455.18{\pm}35.61$ and form the third recasting. the result were $518.38{\pm}37.68$ and over. The change of the hardness difference between each recasting was as follow; The hardness difference between the first casting and the second recasting was $35.25{\pm}31.93$ and that between the second recasting and the third recasting was $63.20{\pm}54.02$. There was a statistically significant difference(P<0.01) in the above hardness, however, there was little difference on the whole. And after the third recasting, the hardness grew high a little bit. That is why low-melting metals such as Cr, Mn, Cu of alloy ingredient was evaporated or there was an effect of changes in metal crystal structure, I suppose. 2) The result of the tensile strength measurement. There was a statistically significant difference(P<0.01) between the first casting and the second, the fourth recasting, however. there was little difference in general.

  • PDF