• 제목/요약/키워드: Circulation Frequency

검색결과 218건 처리시간 0.021초

서울지하철의 저주파소음 특성 (Low Frequency Characteristic of Seoul Subway Noise)

  • 정성수;신수현;김호철;이우섭
    • 대한환경공학회지
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    • 제27권11호
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    • pp.1193-1197
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    • 2005
  • 사람의 귀에 들리지 않는 초저주파음을 비롯하여 200 Hz 이하의 저주파소음은 순환기, 호흡기, 신경, 내분비 등 사람의 생리에 영향을 미치는 것으로 알려져 있다. 이에 몇몇 국가들은 나름대로 저주파소음의 측정법과 평가 기준안을 마련한 상태이다. 본 연구에서는 대중교통 수단인 서울지하철을 대상으로 객차 내와 승강장에서의 저주파소음레벨과 스펙트럼을 조사하였다. 측정결과 객차 내 소음레벨은 지하철 운행속도와 곡선구배 등에 따라 차이는 있었으나, 주파수 $1{\sim}200\;Hz$ 대역에서 $60{\sim}105\;dB$로 나타났다. 특히 8 Hz에서의 소음 피크 값은 객차의 길이에 대한 공명주파수에 해당됨을 알 수 있었다. 승강장에서의 소음은 객차 내 소음보다 상대적으로 소음레벨이 낮게 측정되었는데 이것은 차량 도착 혹은 출발 시의 속력이 운행 시의 속력보다 낮기 때문으로 판단된다. Ochiai의 소음에 의한 인체영향 연구를 고려할 때, 객차 내 소음은 주파수 $20{\sim}80\;Hz$ 구간에서 압박감을 줄 수 있기 때문에 주목할 필요가 있다.

1급 응급구조사의 직무분석에 관한 연구 (A study on the job description of paramedics)

  • 손인아
    • 한국응급구조학회지
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    • 제9권1호
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    • pp.43-53
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    • 2005
  • The purpose of this study was to survey a perception of frequency & importance level of job performance, from 249 paramedics who were working at fire station. The job related activities of 4 duties, 18 tasks and 145 task elements were checked by 4 rating scale. The data were analyzed using a SPSS program for descriptive statistics. The results of the study were as follows ; 1. Some of the most frequent tasks were medical tx, managing people & organization, trauma care, pt assessment, general coping skill 2. Some of the most frequent task elements were preparation of written reports, operation of pt lifting supplies, transportation of patients on stretchers, administration of cervical collar and utilization of scoop stretcher. 3. Some of the highest level of importance in task were resuscitation of circulation, surgical tx, safety & infection control, environmental emergency care, trauma care. 4. Some of the highest level of importance in task elements were administration of cervical collar, adult CPR, infant CPR, child CPR, and AED. 5. The highest level of task elements in perception of frequency & importance were administration of cervical collar, infection control after pt care, utilization of long back board, disinfection of ambulance after ride a long, care of chest pain pt, care of unconscious pt, tx of asthma. 6. A difference between frequent & importance score were due to lack of supplies(41%), structural problems(30%) and medical control system(16%), lack of skills(10%), Suggestion; 1. This paper would be more reliable and confirm through wilder range of survey. 2. It would be necessary of more depth survey through dacom study from paramedic. 3. Development of field oriented protocol & curriculum that based on task elements which have high score of both frequency & importance level is required.

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광중합형 임시충전재의 미세누출에 관한 실험연구 (An Experimental Study on Microleakage in Light-activated Temporary Filling Materials)

  • 황수현;유지수;김선주
    • 치위생과학회지
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    • 제11권4호
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    • pp.333-337
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    • 2011
  • 본 실험에서는 광중합형 임시충전재의 사용기간(1일 후, 3일 후, 7일 후)동안 구강 내의 수분과 온도변화 및 교합력에 의한 미세누출의 가능성을 알아보기 위하여 무게 및 압축강도를 측정하고 열 순환 횟수에 따라 충전재와 와동면 사이의 미세누출을 평가하고자 2종의 광중합형 임시충전재를 사용하여 실험한 결과는 다음과 같다. 1. 광중합형 임시충전재는 사용기간에 따라 측정한 무게는 증가되었다. 제품 간의 비교결과는 Quicks의 무게가 더 높게 나타났다. 2. Spacer의 압축강도는 사용기간에 따라 유의한 차이가 있으나 Quicks의 압축강도에서는 유의한 차이가 나타나지 않았다. 유의한 차이를 보인 Spacer에서는 3일차에서 압축강도가 크게 증가되었다. 3. 열 순환 횟수에 따른 미세누출은 7,000번 실시한 군에서 미세노출이 가장 높게 나타났고, 1,000번 실시한 군과 3,000번 실시한 군은 7,000번 실시한 군보다 통계학적으로 낮은 미세누출을 나타내었다. 4. 사용기간에 따른 무게와 압축강도 및 미세누출사이의 상호연관성이 나타났다. 본 연구에서는 사용기간 경과에 따라 미세누출의 증가를 가져왔으나 수복 후 시간이 경과함에 따라 미세누출이 증가하는 것은 자명한 사실이므로 향후 광중합형 임시충전재의 미세누출을 평가를 위해서는 습식분석을 통하여 화학적 결합을 유도하는 재료의 조성을 분석하는 방법을 부여하는 것이 미세누출 평가에 적절하다고 사료된다.

2008년 태풍 특징 (Characteristics of Tropical Cyclones over the Western North Pacific in 2008)

  • 차은정;황호성;양경조;원성희;고성원;김동호;권혁조
    • 대기
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    • 제19권2호
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    • pp.183-198
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    • 2009
  • The purpose of this study is to summarize the tropical cyclone (TC) activity of 2008 over the western North Pacific including the verification of the official track and intensity forecast errors of these TCs. The TC activity - frequency, Normalized Typhoon Activity (NTA), and life span - was lower than 58-year (1951-2008) average. 22 tropical cyclones of tropical storm (TS) intensity or higher formed in the western North Pacific and the South China Sea in 2008. The total number is less than 58-year average frequency of 26.4. Out of 22 tropical cyclones, 11 TCs reached typhoon (TY) intensity, while the rest 11 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - six STS and five TS storms. One typhoon KALMAEGI (0807) among them affected the Korea peninsula. However, no significant impact - casualty or property damage - was reported. On average of 22 TCs in 2008, the Korea Meteorological Administration (KMA) official track forecast error for 48 hours was 229 km. There was a big challenge for individual cyclones such as 0806 FENGSHEN and 0817 HIGOS presenting significant forecast error, with both intricate tracks and irregular moving speed. The tropical cyclone season in 2008 began in April with the formation of NEOGURI (0801). In May, four TCs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to August. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2008 summertime. The 2008 TC activity has continued the below normal state since mid 1990s which is apparent the decadal variability in TC activity.

정보봉사의 효율을 높이는 요인분석 (A Study on the Factors Increasing the Effectivness of Information Services -with Special Reference to Information Service Units within Research Institutes)

  • 이진영
    • 한국문헌정보학회지
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    • 제24권
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    • pp.73-112
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    • 1993
  • The purpose of this study is to identify what are the common characteristics which enable the information management offices of research institutes to provide information services with their companies in effective ways, and furthur, in other to clarify what factors helf the improvement of effectiveness of information services. I have made on-the-spot investigations for the confirmation of present conditions of information service units of research institutes, their statistic data, and their managerial state. I have restricted my research to 36 information service units, as research targets, which are located in Changwon, Choongchong, and Kyongin areas as the reason mentioned in the introduction, and from their research data they keep, I have classified the top 10 information service units as Group A which show the most frequent use or application frequency of research data per a researcher, where as the lowerest 10 information service units are classified as Group B by the same evaluation of application frequency of their data. Then, the result of the comparision between Group A which provide high information services in effective ways and Group B which provide low information services with poor management leads me to identify the following characteristics in terms of the analyses of utilization of the data they process: 1. Those information service units in Group A have more volumes of books and information data, and annual increasing rates of books and informations are higher than those of Group B. 2. The regulations of book circulation in Group A are prescribed for the benefits of users, and if a long-term loan is not permitted, they are allowed to borrow more books at a time than in Group B. 3. The proportion of librarians to researchers is high, the librarians' career is long and their professional education background (the rate of librarians who majored in library science and information) is high In Group A. 4. Most of the directors of information service units are those who majored library science and information, and for the most part, librarians are promoted to the directors of information service units in Group A. 5. The information service units are managed directly under the directors of research institutes in their organization in Group A. 6. The information service units offer an education for information utilization to researchers as one of their managerial programs, and the contents of education are diverse, rich and informative in Group A. 7. The kinds of informations are various in Group A such as, SDI, prompt reports of contents of new informations, circulation of newly published publications, translation service, information analyses, critical reviews, etc. 8. The information service units in Group A have joined various cooperative systems which are aimed at cooperation, co-ownership of resources and informations. These findings lead me to argue that the hypothesis suggested in the introduction of this thesis has been proved without exception.

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고등학교 공통 과학 강의에서 교사에 따른 역동적 구조의 정량적 비교 분석 (A Comparative Analysis of the Kinetic Structure in Lectures on a High School Science)

  • 유승근;이준상
    • 한국과학교육학회지
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    • 제20권4호
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    • pp.505-509
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    • 2000
  • 담화단위의 연관도를 측정하는 평균기본계수 $(\bar{B}_1)$, 평균가중계수 $(\bar{B}_2)$ 그리고 진행도 (P)는 다음과 같다. T1($\bar{B}_1$, 0.21: $\bar{B}_2$, 0.86: P. 0.79), T2($\bar{B}_1$, 0.02:$\bar{B}_2$, 0.85: P. 0.80), T3($\bar{B}_1$, 0.22: $\bar{B}_2$, 0.83: P.0.78) and T4($\bar{B}_1$, 0.14: $\bar{B}_2$, 0.82: P. 0.86), T4 교사는 다른 교사들에 비해 낮은 역동적 구조를 나타냈으나 수업은 빠른 진행도를 보였다. 총 담화단위 수, 어소의 총 빈도 수, 어소의 종류 수는 T1, T2, T3,T4 교사의 순으로 나타났다. 결과적으로 T4 교사는 다른 교사에 비해 수업 내용의 역동적 구조가 전체적으로 볼 때 낮은 수준을 보였는데, 그 주된 이유는 T4 교사는 수업 준비를 체계적으로 하지 않아, 수업내용이 상대적으로 적었기 때문으로 추측된다. 게다가 T4 교사가 담당하고 있는 학급이 1개 학급이기에 반복적인 수업이 이루어지지 않아 자기 분석의 기회가 없었고, 수업의 내용이 전공 영역과의 관련성이 적었으며 교직 경력 또한 다른 교사보다 낮았기 때문으로 사료된다.

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운동과 음악을 이용한 노래부르기가 노인의 생리적 변화, 인지기능 및 우울에 미치는 효과 (The Effects of Singing Program Combined with Physical Exercise of Physiologic Changes, Perception Function and Degree of Depression in the Elderly Women)

  • 정영주;민순
    • Journal of Korean Biological Nursing Science
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    • 제3권2호
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    • pp.35-50
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    • 2001
  • This study was conducted for the evaluation of the effects of singing program combined with physical exercise on the physiologic changes, perception function and degree of depression. The subjects were the members of elderly women's glee club in D care center for the elderly, who have been singing for more than 6 months. 30 members were allocated to study group and 30 to control group. The singing program designed for both physical therapy and music therapy was consisted of initial physical exercise, singing art songs and classical song and the finishing physical exercise. This program was performed twice a week and about forth minutes was consumed for one session. We checked the heart rate, peripheral arterial oxygen saturation, perception function and degree of depression before and after the program. We used a pulse oxymeter to check the heart rate to oxygen saturation and a questionnaire for the evaluation of perception function and degree of depression. We need SPSS program for data analysis. The results of the investigated personnel complying with general characteristics were analyzed by frequency, two groups by t-test, data before and after the program by paired t-test, respectively. The results were as follows. 1) Heart rate after the program was significantly lower than that before program in test group(p<0.05). 2) Peripheral oxygen saturation after the program was significantly higher than that before the program(p<0.05). 3) Ability to match the right sign with a certain predetermined number was improved after the program. The frequency of wrong matching the sign with number before program was 30. But the frequency was decreased to 8 after the program. 4) Ability to calculate was improved after the program. The frequency of wrong calculation before the program was $1.10{\pm}1.94$. But the frequency after the program was decreased to $0.97{\pm}1.84$. 5) The degree of depression after the program($2.07{\pm}0.49$) was significantly lower than that before program(p<0.001). These results show that singing program combined with physical exercise improves the oxygen delivery to peripheral circulation, stability of heart function, the perception function(calculating and matching ability) and decreases the degree of depression. In conclusion, singing program combined with physical exercise can be used for the effective measure to improve the health of elderly and prevent dementia.

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지첨용적맥파의 파형분석과 주파수분석에 대한 문헌적 연구 (A Systemic Review of Pulse Contour Analysis and Fourier Spectrum Analysis on the Photoplethysmography of Digit)

  • 남동현;박영배;박영재;신상훈
    • 대한한의진단학회지
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    • 제11권1호
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    • pp.48-60
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    • 2007
  • Palpation of the pulse has been used in Korean traditional medicine since ancient times to assess physical health. Pulse wave contour may be obtained by measuring arterial pressure or blood volume change of skin. The latter is called as Photoplethysmography(PPG) or digital volume pulse(DVP). The PPG signal is measured by a device comprising an infrared light sourece and a photodetector. Although less widely used, this technique deserves further consideration because of its simplicity and ease of use. The contour of the PPG is formed as a result of a complex interaction between the left ventricle and the systemic circulation. It usually exhibits an early systolic peak and an early diastolic peak. the first peak is formed mainly by pressure trasmitted along a direct path from the left ventricle to the finger. The second peak is formed in part by pressure transmitted along the aorta and large arteries to sites of impedance mismatch in the lower body. The contour of the PPG is sensitive to changes in arterial tone and is influenced by ageing and large artery stiffness. Measurements taken directly from the PPG or from its second derivative can be used to assess these properties. In some mathematical approaches, the extraction of periodic components using frequency analysis was tried to analysis of the PPG. But we don't understand yet what kind of factor in the cardiovascular system or human body is related with the respective specific Fourier components of PPG. This review describes the background to measurement principles, representative contour, contour analysis and frequency domain analysis of PPG, and current and future.

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2007년 북서태평양에서의 열대저기압 발생 특징 (Characteristics of Tropical Cyclogenesis over the Western North Pacific in 2007)

  • 최기선;김백조;이성로;김호경;박종길;이지선
    • 한국환경과학회지
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    • 제18권5호
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    • pp.539-550
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    • 2009
  • This study found that tropical cyclones (TCs) formed for fall in 2007 over the western North Pacific were distributed in high-latitudes comparing to 56-year (1951-2006) climatological mean. The frequency and latitude of TC genesis became higher than 56-year climatological mean from September onward in 2007 and all the TCs that formed to the north of 20$^{\circ}$N was also distributed after September in 2007. These characteristics of TC genesis for fall in 2007 could be confirmed through analyzing various variables, such as a large-scale atmospheric circulation, outgoing longwave radiation (OLR), vertical zonal wind shear, and sea surface temperature (SST). On the other hand, a frequency of the TC that occurred to the north of 200N showed a clear interdecadal variation and its decreasing trend was distinctive in recent years. Its intensity was also weaker that TCs that did to the south of 20$^{\circ}$N. However, a latitude of TC genesis showed an increasing trend until recent years, whose variation was consistent with trend that through a SST analysis, warm SST went north in recent years.

The Effect of Pulsatile Flow on Ultrafiltration In-Vitro Study and Comparison with Roller Pump

  • Lee K.;Jeong J. H.;Mun C. H.;Lee J. C.;Min B. G.
    • 대한의용생체공학회:의공학회지
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    • 제26권5호
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    • pp.337-341
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    • 2005
  • Blood pulsation has been reported to have an advantageous effect on extracorporeal blood circulation. However, the study of pulsatile blood flow in renal replacement therapy is very limited. The in-vitro experimental results of pulsatile blood flow on ultrafiltration, when compared with the conventional roller pump, are described in this paper. Methods: Blood flow rate (QB) and transmembrane pressure (TMP) were considered as regulating factors that have an influence on ultrafiltration. Experiments were performed under the condition of equal TMP and OB in both pulsatile and roller pump groups, Several kinds of hollow fiber dialyzers were tested using distilled water containing chemicals as a blood substitute. Mean TMP (mTMP) varied from 10 to 90mmHg while the QB was 200ml/min. Results: Ultrafiltration rate (QUF) was found to be linearly proportional to TMP, whereas QB had little influence on QUF. In addition, QUF was higher in the pulsatile group than the roller pump group at the identical TMP. Conclusion: In the controlled test, QUF increased solely as a consequence of blood pulsation, which implies that the pulse frequency represents an additional and important clinical variable during renal replacement therapy.