• 제목/요약/키워드: Two-way ranging

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중첩된 처프 신호를 이용한 수중 이동체의 거리 추정 (Range estimation of underwater vehicles using superimposed chirp signals)

  • 라형인;이경원;윤창현;김기만
    • 한국음향학회지
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    • 제42권6호
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    • pp.511-518
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    • 2023
  • 수중 이동체의 시험평가 과정에서 정확한 거리 추정은 중요한 요소 가운데 하나이다. 특히, 도달 시간 값을 이용하여 거리를 추정하는 경우 상관 특성 등으로 인해 처프 신호인 Linear Frequency Modulation(LFM)과 같은 신호의 적용성이 높다. 하지만 이동성이 있는 도플러 천이 환경에서는 거리-도플러 커플링 효과로 인하여 측정 오류가 발생할 수 있다. 이에 본 논문에서는 거리-도플러 커플링 효과를 보상하여 도달 시간 값의 측정 오류를 감소시키는 신호를 제시한다. 제안된 신호는 2종류의 LFM 신호를 중첩하여 구성하였으며, 거리-도플러 커플링 효과를 최소화할 수 있다. 시뮬레이션을 통해 제안된 신호가 수중 이동체의 거리 추정에 있어서 거리-도플러 커플링 효과를 보상하여 도달 시간 값의 측정 오류를 줄이는 방법임을 확인하였다.

의료서비스 마케팅을 위한 품질지각과 만족에 관한 연구 (A Study on Qulity Perceptions and Satisfaction for Medical Service Marketing)

  • 유동근
    • 간호행정학회지
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    • 제2권1호
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    • pp.97-114
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    • 1996
  • INSTRODUCTION Service quality is, unlike goods quality, an abstract and elusive constuct. Service quality and its requirements are not easily understood by consumers, and also present some critical research problems. However, quality is very important to marketers and consumers in that it has many strategic benefits in contributing to profitability of marketing activities and consumers' problem-solving activities. Moreover, despite the phenomenal growth of medical service sector, few researchers have attempted to define and model medical service quality. Especially, little research has focused on the evaluation of medical service quality and patient satisfaction from the perspectives of both the provider and the patient. As competition intensifies and patients are demanding higher quality of medical service, medical service quality and patient satisfaction has emerged as a critical research topic. The major purpose of this article is to explore the concept of medical service quality and its evaluation from both nurse and patient perspectives. This article attempts to achieve its purpose by (1)classfying critical service attibutes into threecategories(satisfiers, hygiene factors, and performance factors). (2)measuring the relative importance of need criteria, (3)evaluating SERVPERF model and SERVQUAL model in medical service sector, and (4)identifying the relationship between perceived quality and overall patient satisfaction. METHOD Data were gathered from a sample of 217 patients and 179 nurses in Seoul-area general hospitals. From the review of previous literature, 50 survey items representing various facets of the medical service quality were developed to form a questionnaire. A five-point scale ranging from "Strongly Agree"(5) to "Strongly Disagree"(1) accompanied each statement(expectation statements, perception statements, and importance statements). To measure overall satisfaction, a seven-point scale was used, ranging from "Very Satisfied"(7) to "Very Dissatisfied"(1) with no verbal labels for scale points 2 through 6 RESULTS In explaining the relationship between perceived performance and overall satisfaction, only 31 variables out of original 50 survey items were proven to be statistically significant. Hence, a penalty-reward analysis was performed on theses 31 critical attributes to find out 17 satisfiers, 8 hygiene factors, and 4 performance factors in patient perspective. The role(category) of each service quality attribute in relation to patient satisfaction was com pared across two groups, that is, patients and nurses. They were little overlapped, suggesting that two groups had different sets of 'perceived quality' attributes. Principal components factor analyses of the patients' and nurses' responses were performed to identify the underlying dimensions for the set of performance(experience) statements. 28 variables were analyzed by using a varimax rotation after deleting three obscure variables. The number of factors to be extracted was determined by evaluating the eigenvalue scores. Six factors wereextracted, accounting for 57.1% of the total variance. Reliability analysis was performed to refine the factors further. Using coefficient alpha, scores of .84 to .65 were obtained. Individual-item analysis indicated that all statements in each of the factors should remain. On 26 attributes of 31 critical service quality attributes, there were gaps between actual patient's importance of need criteria and nurse perceptions of them. Those critical attributes could be classified into four categories based on the relative importance of need criteria and perceived performance from the perspective of patient. This analysis is useful in developing strategic plans for performance improvement. (1) top priorities(high importance and low performance) (in this study)- more health-related information -accuracy in billing - quality of food - appointments at my convenience - information about tests and treatments - prompt service of business office -adequacy of accommodations(elevators, etc) (2) current strengths(high importance and high performance) (3)unnecessary strengths(low importance and high performance) (4) low priorities(low importance and low performance) While 26 service quality attributes of SERPERF model were significantly related to patient satisfation, only 13 attributes of SERVQUAL model were significantly related. This result suggested that only experience-based norms(SERVPERF model) were more appropriate than expectations to serve as a benchmark against which service experiences were compared(SERVQUAL model). However, it must be noted that the degree of association to overall satisfaction was not consistent. There were some gaps between nurse percetions and patient perception of medical service performance. From the patient's viewpoint, "personal likability", "technical skill/trust", and "cares about me" were most significant positioning factors that contributed patient satisfaction. DISCUSSION This study shows that there are inconsistencies between nurse perceptions and patient perceptions of medical service attributes. Also, for service quality improvement, it is most important for nurses to understand what satisfiers, hygiene factors, and performance factors are through two-way communications. Patient satisfaction should be measured, and problems identified should be resolved for survival in intense competitive market conditions. Hence, patient satisfaction monitoring is now becoming a standard marketing tool for healthcare providers and its role is expected to increase.

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항공 LiDAR 원자료 필터링 조건에 따른 산림지역 수치표고모형 정확도 평가 (The Accuracy Evaluation of Digital Elevation Models for Forest Areas Produced Under Different Filtering Conditions of Airborne LiDAR Raw Data)

  • 조승완;최형태;박주원
    • 농업생명과학연구
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    • 제50권3호
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    • pp.1-11
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    • 2016
  • 3차원 지형정보를 얻기 위하여 항공 LiDAR(Light Detection and Ranging)자료 기반 수치표고모델(Digital Elevation Model, DEM) 생성에 대한 연구들에 대한 관심이 지속적으로 높아져 왔다. 항공 LiDAR 원자료로부터 정확도가 높은 DEM을 생성하기 위해서는 3차원 점군에서 비지면점을 제외시키고 지면점만을 포함시키는 필터링(filtering)과정이 중요하다. 특히, 필터링을 구성하는 알고리즘의 패러미터 값 변화에 따라 산출되는 결과물들에 차이가 발생하고 정확도에 영향을 준다. 따라서 본 연구는 화천, 양주, 경산 및 장흥 유역 대상지의 항공 LiDAR 자료로부터 Fusion 소프트웨어를 이용하여 LiDAR DEM을 생성하는 GroundFilter알고리즘의 Mean패러미터(GFmn) 수준 변화가 LiDAR DEM 결과물의 정확도에 어떤 영향을 주는지 분석하였다. GFmn 수준 변화에 따른 정확도에 대한 영향 여부를 분석하기 위해 일원배치분산분석을 실시하였고, 그 결과 GFmn의 수준 변화에 따라 정확도에 대한 영향이 유의미하게 나타났다(F-value: 4.915, p<0.01). 이 후 각각의 GFmn 수준들을 다른 수준들과 차이가 있는지 여부로 묶기 위하여 사후검정을 실시하였다. 사후분석을 통해 잔차의 평균 차이에 따라 '7, 5, 9, 3'과 '1' 두 집단으로 나뉘었다. 아울러 보다 정확한 해발고도를 표현하는 LiDAR DEM 생성하는데 적정 GFmn은 '7' 조건일 때로 나타났다. 이 연구를 통해 보다 정확한 해발고도를 표현하는 LiDAR DEM을 생성할 수 있는 패러미터 값을 제안하였다.

도시 및 농촌 일부지역의 강하분진과 여과액중의 이온농도 (Dustfalls and Various Ion Concentrations in Their Filtrates in an Urban and in a Rural Districts)

  • 홍연표
    • Journal of Preventive Medicine and Public Health
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    • 제18권1호
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    • pp.59-71
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    • 1985
  • During a period from February 1st to November 30th in 1983, measurements were made twice a month on dustfalls and concentrations of various cations ana anions in their filtrates in an urban (Heuksuk-dong, Seoul) and in a rural (Ansung) districts. Standard British Deposit Gauge method was applied for collection of dustfalls and ion chromatographic method using Ion Chromatograph 10 (Dionex, U.S.A.) for determination of cation and anion concentrations. The results obtained were as follows: 1. Annual mean values of dustfalls were $8.30{\pm}5.09tons/km^2/month$ in an urban and $6.20{\pm}0.82tons/km^2/month$ in a rural districts. And annual mean values of pH of filtrates of the collected samples were $5.3{\pm}0.76$ in an urban and $6.0{\pm}0.82$ in a rural districts. 2. Annual mean concentrations of common cations and anions in their filtrates were as follows: urban rural (unit: ppm) $$Na^{+}\;1.7{\pm}1.30\;1.9{\pm}1.86$$ $$NH^{+}_{4}\;2.4{\pm}1.60\;1.3{\pm}1.59$$ $$K^{+}\;0.7{\pm}0.47\;1.5{\pm}3.79$$ $$Ca^{++}\;5.3{\pm}0.95\;3.4{\pm}2.58$$ $$Mg^{++}\;0.7{\pm}0.89\;0.5{\pm}0.83$$ $$Cl^{-}\;2.0{\pm}1.31\;4.0{\pm}2.35$$ $$NO^{-}_{3}\;4.0{\pm}2.35\;2.7{\pm}1.31$$ $$So^{--}_{4}\;16.9{\pm}17.40\;6.8{\pm}8.00$$ Some of anions such as $Br^{-},\;{PO_4}^{-3}\;and\;{NO_2}^{-}$ were scarecely detected and $F^{-}$ was measured at very low concentrations ranging from 0.1 to 0.5 ppm in Feb., Oct. and Nov. in an urban and in Feb. in a rural districts. 3. By two-way analysis of variance with 4 replications for dustfalls, pH and concentrations of various ion by district and month of a year, statistically significant differences were noted in dustfalls (p<0.01), pH (p<0.01) and concentrations of various ion (p<0.01) by month of a year, and in dustfalls (p<0.05) and concentrations of various ion such as ${NH_4}^{+},\;Ca^{++},\;{NO_{3}}^{-}\;and\;{SO_4}^{--}$ (p<0.01) by district. 4. There were statistically significant differences pH in Spring (Feb., Mar and Apr.) (p<0.01) and in ${SO_4}^{--}$ in Autumn (Aug., Sept., Oct. and Nov.) (p<0.05) between the two districts.

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어항투자사업의 경제성 평가에 관한 연구 (The Study on the Economic Appraisal of Fishing Port Investments)

  • 정형찬
    • 수산경영론집
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    • 제14권2호
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    • pp.15-68
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    • 1983
  • From the economic point of view the fishing port is the complex of installations on land, organized to serve the fishing fleet and its cargo, and is the main link in the production chain of all components of the fishing industry, with the aim of achieving the planned targets with the minimum cost. Fishing port investment decisions have had significant impact on the development aims of Korean fisheries. Fishing port investments in Korea are made mostly by public or semipublic port authorities. Such investments should be judged not purely on the basis of financial profitability but rather on the extent to which they serve the development aims of the fishing industry. This makes the economic appraisal process more complex and presents certain problems in correctly quantifying the economic costs and benefits of the fishing port projects. This study concentrates more on the theoretical economic appraisal models than on the purely financial aspects of fishing port investments and points out the difference between the two approaches. In the result, there is clearly an element of judgment as to whether or not a shadow price needs to be used in estimating economic benefits and costs. From this viewpoint, some attempts are made to provide definitions of the possible economic benefits and costs, and methods for estimating and evaluating them in Part III and IV. Especially queueing theory is applied in the calculation of economic benefits. When a project is contemplated and analysis shows it to Lave a positive NPV, one question that arises is whether it should be implemented now or delayed. In this paper, the first year rate of return method is regarded as a more concise way of solving the timing of investment, At the end of Part IV, risk analysis of fishing port investments is considered. It can be handled in a number of ways, ranging from informal judgment to complex statistical analyses involving large-scale computer models, This paper recommends that evaluators of fishing port investments use the sensitivity analysis indicating exactly how much NPV will change in response to a given change in an input variable, other things held constant. Decisions regarding the amount of capacity to provide must be made in fishing port investments. Providing too much service would involve excessive capital costs. On the other hand, not providing enough service capacity would cause the waiting line of fishing vessels to become excessively long at times. Therefore, in Part V, the optimal number of berths and berth productivity in fishing port are defined as follows: Minimize E(TC) = E(WC)+E(SC) The minimum of this function is the solution and that is the optimal number of berth and berth productivity in fishing port.

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전기장에 의해 생성된 미세기포를 이용한 페놀의 오존산화 (Oxidation of Phenol Using Ozone-containing Microbubbles Formed by Electrostatic Spray)

  • 신원태;정유진;성낙창
    • 대한환경공학회지
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    • 제27권12호
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    • pp.1292-1297
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    • 2005
  • 상수나 하수처리장에서 쓰이는 오존처리는 물질전달에 제약을 받는 공정임은 알려져왔다. 이런 물질전달의 한계를 극복하는 방법으로 매우 효과적인 것은 오존가스를 함유한 기포의 크기를 줄임으로써 물질전달에 필요한 접촉면적을 넓히는 것이다. 오존의 전달을 크게 하기 위한 방법으로서 본 연구에서는 전기장분사(Electrostatic spraying: ES)를 사용하였다. 실험에서는 ES와 기포발생판을 비교하였는데 ES실험에서는 전압을 0 kV에서 4 kV 범위까지 높여주어 물질전달효과를 살펴보았고 기공크기가 다른 두 가지 기포발생판(미세기공: 기공크기 $10{\sim}15{\mu}m$, 중간기공: 기공크기 $40{\sim}60{\mu}m$)을 사용하여 물질전달효율을 비교 분석 하였다. 물질전달효율은 시간의 경과에 따른 용존오존농도의 측정과 페놀의 산화시간으로 간접 계산하였다. 실험 결과 ES의 경우 전압을 0 kV에서 4 kV까지 올렸을 때 기포의 크기가 작아짐으로 인해 오존전달율을 약 40% 정도 향상시킬 수 있었다. 또한 ES와 기포발생판의 물질전달 비교실험에서 미세기공 기포발생판보다 4 kV의 ES가 더 효과적임을 알 수 있었다.

손자녀를 돌보는 조부모의 부담감과 사회적 지지 (The relationship between the burden and the social support of grandmothers caring their grandchildren)

  • 권인수
    • Child Health Nursing Research
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    • 제6권2호
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    • pp.212-223
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    • 2000
  • The purposes of this research were to add to the developing knowledge base about the burden and social support of grandmothers involved with caring grandchildren, and to examine whether a significant relationship exists between their burden and social support perceived by the grandmothers. A convenience sample of 102 grandmothers was recruited from five collective apartment areas at a small city in Korea. The criteria of selection of sample were that the grandmothers were raising their grandchildren under the age of 36 months for 3 months or longer at own or gandchildren's home. The instruments used were a 15-item multidemensional burden scale and a 8-item social support scale. Both scales were self report, five point Likert type scales. The higher the score, the higher the degree of burden and social support. Data was collected by two prepared research assistants visiting subjects' home from December 10, 1998 to March 20, 1999. The collected data were analysed using mean, t-test, one-way ANOVA, and Pearson's correlation coefficient computed by SPSS software. The results were as follows. 1. In the age distribution of grandmothers, the over half of subjects(58.8%) were under 60 years old. The majority(69.6%) of subjects were married at time of data collection. 79(77.5%) of the sample reported that their perceived health status was good or over. 2. The burden of the grandmothers was not scored high, and the item means on burden scale were ranged from 2.26 to 4.19 out of 5. 'Short of private time'(4.19) had the highest score, followed by 'fatigue'(3.92), 'short of rest'(3.75), and 'short of contact with friends and neighbors'(3.62). The lowest item was 'family doesn't help me'(2.26), and followed by 'family doesn't understand me'(2.33), 'angry with family' (2.43), and 'angry while caring for grandchild'(2.60). 3. There were significant relationships between the burden and present health status(p<.01), childcaring confidence(p<.01), and motive of caring(p<.01). 4. The score of social support, was ranging from 3.61 to 4.01 out of 5. 5. The relationship between burden and social support was found to be correlated negatively. The relationship was statistically significant(γ= - .2833, p<.001). In conclusion, it was found that the burden was not high and burden of grandmothers caring grandchildren was correlated negatively to social support. Therefore, these results provide a basis for developing a nursing intervention to reduce the burden of grandmothers.

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대응일치분석을 이용한 4년제 대학졸업자들의 취업훈련기관별 노동시장 성과에 영향을 미치는 요인 (The Determinants of Labor Market Outcomes in Four-year graduates through Principal Component Analysis and Correspondence Analysis By training institution)

  • 채희원
    • 한국산학기술학회논문지
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    • 제18권4호
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    • pp.235-241
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    • 2017
  • 본 연구는 한국교육고용패널(Korean Education and Employment Panel ; KEEP) 데이터를 활용하여 국내 4년제 대학 졸업자들을 대상으로 노동시장 진입을 위한 성과 요인을 고찰하고, 훈련기관에 따라 노동시장 성과가 어느 정도의 관계를 맺고 있는가를 탐색하는 것을 주 목적으로 첫 일자리 이행기간에 영향을 미치는 노동시장 성과요인을 분석하였다. 노동시장 성과를 각각 (1) 첫 일자리 이행기간 (2) 고용형태 (3) 임금수준으로 명명하였다. 응답자가 취업을 위하여 훈련받은 기관의 특징가진 명목변수와 대응일치분석(correspondence analysis)을 실시하였다. 양자 간의 연관성을 가시적인 방법으로 나타내기 위함이다. 그 결과 첫째, 첫 일자리 이행기간이 가장 짧은 훈련기관은 공공기관으로 사설학원, 대학 순으로 분석되었다. 둘째, 고용형태 별로는 공공기관은 사설학원과 대학과 비교하여 상대적으로 일용직의 비율이 높았다. 셋째, 임금수준 별로는 공공기관의 경우 임금수준 1범위에서 3범위까지의 분포를 보였고, 사설학원의 경우는 임금수준 2범위에서 4범위까지 높은 분포를 보였다. 이러한 결과를 기반으로 청년층의 사회진출 시 훈련기관별 노동시장 성과의 차이를 분석해 볼 수 있어, 훈련기관별 청년층 구직자의 특성에 대해서 알 수 있는 기초 자료를 제공하고, 고용과 교육 고용복지를 포괄하는 정책이 확충되어야 함을 제언하였다.

Appropriate level of alfalfa hay in diets for rearing Simmental crossbred calves in dryland China

  • Kobayashi, Nobuyuki;Hou, Fujiang;Tsunekawa, Atsushi;Chen, Xianjiang;Yan, Tianhai;Ichinohe, Toshiyoshi
    • Asian-Australasian Journal of Animal Sciences
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    • 제31권12호
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    • pp.1881-1889
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    • 2018
  • Objective: In dryland areas of China, alfalfa hay (AH) is a possible substitute for concentrate feed for beef cattle. To evaluate the potential benefits of this substitution, we studied the effect of the ratio of AH intake to total dry matter (DM) intake on average daily body-weight gain (ADG), dietary energy utilization status, and economic benefit in Gansu province. Methods: In each of two feeding trials in 2016 (trial 1 [T1], July 3 to 17; trial 2 [T2], August 15 to September 23), crossbred male Simmental calves were allocated to low AH (LA), medium AH (MA), and high AH (HA) feeding groups (n = 4 per group). The target ADG was set as 1 kg for both trials. In a one-way-layout design based on conventional feeding practices in the province, calves received diets containing the different AH amounts, with a constant ratio of corn stover:total DM and decreasing rations of concentrate feed proportional to the increase in AH. Calves in T1 received AH at 15% (T1-LA), 23% (T1-MA), or 31% (T1-HA) of their dietary DM allowances; those in T2 received 9% (T2-LA), 24% (T2-MA), or 34% (T2-HA) AH. Results: Among the T1 groups, both ADG and economic benefit were highest in T1-LA; whereas in T2, they were higher in the T2-LA and T2-MA groups than in T2-HA. Energy digestibility did not significantly differ among the groups in either trial. The dietary AH inclusion ratios of 14% in the warm season and 8% to 21% in the cool season appeared to yield optimal ADG, metabolizable energy intake, and economic benefit. Conclusion: Low-level inclusion of AH, ranging from 8% to 21%, is a practical approach for beef cattle feeding. This modified feeding regimen likely will promote increased growth performance during the fattening stage of beef steers in dryland areas of Gansu province, China.

한국 육상풍력발전사업의 환경적 지속가능성 평가 연구 - 58개 환경영향평가서 사례에 대한 정량적 분석 - (Analysis of Environmental Sustainability in South Korean Inland Windfarms)

  • 정은해
    • 환경영향평가
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    • 제31권1호
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    • pp.47-62
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    • 2022
  • 풍력발전은 비용 효율적인 신재생에너지원으로 우리나라 뿐 아니라 전세계적으로 빠르게 보급이 확대되고 있다. 환경적 지속가능성을 보장하면서 지속가능한 에너지를 공급하기 위해서는 증거에 기반한 정책수립과 혁신적인 방안 마련이 필요하다. 본 논문은 풍력발전 환경영향평가서 58건의 분석을 통해 1) 국내 육상풍력의 주요 특징이 어떠한가? 2) 환경영향을 최소화하기 위한 사업별 환경적 지속가능성을 분석하는 방법이 있는가?에 대한 해답을 제시하고자 한다. 환경영향평가서에 제시된 개별 육상풍력사업의 환경적 지속가능성과 관련한 변수를 추출하여 이러한 환경변수에 대한 요인분석을 수행하고 개별 변수의 가중치를 계산하여 육상풍력발전의 환경적 지속가능성을 평가할 수 있는 지수를 개발하였다. 이러한 환경적 지속가능성지수는 육상풍력발전의 입지를 고려할 때 활용할 수 있는 유용한 증거에 기반한 의사결정도구로 활용될 수 있을 것이다. 58개 사업은 사업지역의 고도 및 자연성의 정도를 바탕으로 1) 산악형, 2) 목장형, 3) 해안형으로 구분하였다. 본 연구에서는 개별 풍력발전사업에 대한 환경적 지속가능성지수를 성공적으로 계산하였다. 가장 환경적 지속가능성이 큰 사업은 목장형으로 분류된 33번 사업이 1.04였고, 가장 낮은 사업은 산악형으로 분류된 55번 사업으로 -1.44였다. 둘째, 분석결과는 목장형이 환경지속가능성 지수가 평균 0.4551로 환경적 지속가능성이 가장 높고, 해안형이 평균 0.3712으로 중간이었으며, 산악형이 평균 -0.3457로 가장 낮은 것으로 나타났다. 이러한 결과는 육상풍력발전과 관련된 기존의 연구에서 제시된 결과를 보다 계량적으로 증명하고 있으며, 신재생에너지개발과 관련한 정책에 활용할 수 있는 중요한 함의를 제공하고 있다.