• Title/Summary/Keyword: second-order expansion

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Approximation of a Warship Passive Sonar Signal Using Taylor Expansion (테일러 전개를 이용한 함정 수동 소나 신호 근사)

  • Hong, Wooyoung;Jung, Youngcheol;Lim, Jun-Seok;Seong, Woojae
    • The Journal of the Acoustical Society of Korea
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    • v.33 no.4
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    • pp.232-237
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    • 2014
  • A passive sonar of warship is composed of several directional or omni-directional sensors. In order to model the acoustic signal received into a warship sonar, the wave propagation modeling is usually required from arbitrary noise source to all sensors equipped to the sonar. However, the full calculation for all sensors is time-consuming and the performance of sonar simulator deteriorates. In this study, we suggest an asymptotic method to estimate the sonar signal arrived to sensors adjacent to the reference sensor, where it is assumed that all information of eigenrays is known. This method is developed using Taylor series for the time delay of eigenray and similar to Fraunhofer and Fresnel approximation for sonar aperture. To validate the proposed method, some numerical experiments are performed for the passive sonar. The approximation when the second-order term is kept is vastly superior. In addition, the error criterion for each approximation is provided with a practical example.

Use of Home Nursing Therapy and Need of Home Care Equipments (가정간호환자의 치료적 간호서비스 제공과 의료기구 사용 및 요구도)

  • Ryu, Ho-Shin;Park, Chai-Soon;Kim, In-A;Kwon, Young-Dae;Kang, Sung-Wook
    • Research in Community and Public Health Nursing
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    • v.19 no.2
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    • pp.157-166
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    • 2008
  • This study was conducted with whole home care nurses nationwide to provide secondary analyzed data to understand on their usage of medical equipments and their need of them for a month. This study found that treatments given by home care nurses were nelaton catheterization, bladder washing/urethral washing, newborn care, exchange and care for nasogastric tube and suction in that order of frequency. Second, instruments and equipments used for home care were reported to be stethoscope, patient monitor, blood pressure measuring equipment, air flotation mattresses, beds for patients, mattresses, suctioning device sets, enteral feeding equipment and dressing set in that oder of frequency. Moreover, need assessment of medical instruments and equipments showed renal dialysis was most needed and patient monitor, blood pressure measuring equipment, enteral feeding equipment, solution and other supplies for renal dialysis and beds for patient were necessary in that order. In conclusion, the results of this study investigating special treatments and medical instruments and equipments used for home care patients and analyzing patients' need, were expected to be useful for expansion of application of long-term care insurance for the elderly and health insurance as well as for quality control of home care and development of medial instruments and equipments used at home.

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The Effect of Food Service Franchise Selection Factors on Brand Loyalty and Revisit Intention - Focusing on Consumer Survey in Tokyo - (외식 프랜차이즈 선택요인이 브랜드 충성도와 재방문의도에 미치는 영향 연구 -동경(東京)지역 한국 외식 프랜차이즈를 이용하는 소비자 설문조사를 중심으로-)

  • Kim, Seon-Hyen;Hwang, Jae-Hyun
    • Korean Journal of Organic Agriculture
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    • v.25 no.4
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    • pp.663-677
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    • 2017
  • As Korean food service franchise companies sought to advance into around 2,000 new foreign markets, the importance of global management was emphasized. They intensively expanded into Chinese and American markets in 2015 and these two markets account for approximately 40% of total food service franchise companies in foreign countries. Although Japan has huge franchise market, Korean food service franchise companies in Japan only account for 5% of total franchise companies in Asian countries. The purpose of this study is to analyze the relationship between food service franchise selection factors, brand loyalty, and revisit intention of Japanese consumers using Korean food service franchise companies in Japanese food service market, and based on the analysis results, draw the implications for the expansion of Korean food service franchise companies into the Japanese market. Food service franchise selection factors is defined as service and cleanliness, taste, safety and reliability, cost and convenience, and professionalism. The study results can be summarized as follows. First, analysis was performed to identify the effects of food service franchise selection factors on the brand loyalty, it showed that five food service franchise selection factors including professionalism, service and cleanliness, cost and convenience had positive (+) effects on the brand loyalty. One of the most important factors influencing the brand loyalty is professionalism. In order to raise food service franchise's professionalism, it is necessary for the food service franchise companies to establish stronger strategies containing professional operation systems and services compared to general restaurants. Second, analysis was performed to identify the effects of food service franchise selection factors on revisit intention, five food service franchise selection factors, service and cleanliness, safety and reliability, and cost and convenience had positive (+) effects on revisit intention. One of the most important factors influencing revisit intention is safety and reliability. Thus, in order to raise safety and reliability it is important to form trust with consumers by properly utilizing systems of food hygiene and food safety accreditation.

Large Slow-Drift Motions of a Floating Body in Slightly Modulated Waves (해상(海上)에 계류(繫留)된 부유체(浮遊體)의 표류운동(漂流運動) 해석(解析))

  • Dong-J.,Kim;Hang-S.,Choi
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.4
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    • pp.3-14
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    • 1990
  • For a moored body on the sea surface, incident waves with narrow-banded spectra excite the body oscillations of short and long periods. Since the period of slow oscillations can be as long as the natural period of the moored body in horizontal modes, resonance can occur and resulting large motions may cause significant strains in mooring cables. By using the perturbation method of multiple scales, the large slow motion can be analyzed without solving any second-order potentials explicitly. To the leading order, the flows associated with the fast and slow motions interact only parametrically and thus they can be studied separately. It is found that the slow motion strongly depends on the mooring stiffness. In particular, if the moring stiffness is considerably weak compared to the body inertia, the slow motion is highly amplified near resonance. It is also shown that the slow motion is associated with the generation of long waves.

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Semi-Analytical Methods for Different Problems of Diffraction-Radiation by Vertical Circular Cylinders

  • Malenica, Sime
    • International Journal of Ocean System Engineering
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    • v.2 no.2
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    • pp.116-138
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    • 2012
  • As in the other fields of mechanics, analytical methods represent an important analysis tool in marine hydrodynamics. The analytical approach is interesting for different reasons : it gives reference results for numerical codes verification, it gives physical insight into some complicated problems, it can be used as a simplified predesign tool, etc. This approach is of course limited to some simplified geometries (cylinders, spheres, ...), and only the case of one or more cylinders, truncated or not, will be considered here. Presented methods are basically eigenfunction expansions whose complexity depends on the boundary conditions. The hydrodynamic boundary value problem (BVP) is formulated within the usual assumptions of potential flow and is additionally simplified by the perturbation method. By using this approach, the highly nonlinear problem decomposes into its linear part and the higher order (second, third, ...) corrections. Also, periodicity is assumed so that the time dependence can be factorized i.e. the frequency domain formulation is adopted. As far as free surface flows are concerned, only cases without or with small forward speed are sufficiently simple to be solved semi-analytically. The problem of the floating body advancing in waves with arbitrary forward speed is far more complicated. These remarks are also valid for the general numerical methods where the case of arbitrary forward speed, even linearized, is still too difficult from numerical point of view, and "it is fair to say that there exists at present no general practical numerical method for the wave resistance problem" [9], and even less for the general seakeeping problem. We note also that, in the case of bluff bodies like cylinders, the assumptions of the potential flow are justified only if the forward speed is less than the product of wave amplitude with wave frequency.

Transfiguration of intangible cultural assets due to activation of Folk Festival - Gangneung Danoje as the pivot - (민속축제 활성화에 따른 무형문화재의 변용 - 강릉단오제를 중심으로)

  • Hwang, Ru-Shi
    • Korean Journal of Heritage: History & Science
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    • v.36
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    • pp.299-312
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    • 2003
  • Gangneung Danoje does not only have the longest history but also is the largest folk festival in Korea. However, during its long history Gangneung Danoje has not always been the way as it is today. As records reveal, since the Chosun dynasty and through Japanese rule, it has gone through numerous variations and registration processes in order to become a national designated major intangible cultural asset. Especially after it has been appointed as a national major intangible cultural asset Gangneung Danoje has under gone through variety of transformations. First of the few changes is the citizen-lead characteristic. As Gangneung Cultulral Center took charge of Danoje this trait has become prominent. Hereby Chosun dynasty's government lead system has transformed into a civilian lead festival. Second alteration is the enormous scale of expansion and the variations of the characteristic of the festival because of it. Dano event has increased annually from 12 events in 1974 to 58 events by 1999. As the scale of Danoje enlarged the promoters found solutions by providing diversified events in order to satisfy peoples' various aspirations from the festival. However this solution lead to a diversion - from participating festival to a spectating festival. And the last change that occurred is the awareness of the need to develop Danoje into an international festival. This is rather a desire from the government than of the people. In 1994, Korea visiting year as an opportunity this consciousness grew active. For instance, the invitation of mass foreign folk performance in 1999 seems to conform to this policy. The intention to make Gangneung Danoje not only to represent Gangneung but also to represent Korea's folk event can be witnessed. As we enter 21st Century this inclination for international festival has strengthened. Gangneung government has shown enthusiasm to find the future of Danoje by inviting external service corps to assess Danoje. The current inclination appears to be increase its value as an international festival through UNESCO cultural property registration and having this as a foundation make Danoje become an international cultural tourist product. The judgment of this will be made after Gangneung International Folklore Festival 2004.

A Study on the Attracting Strategy of FDI in Gwangju and Jeonnam Region (외국인직접투자 유치전략에 관한 연구 -광주.전남지역을 중심으로-)

  • Shim, Jae-Hee;Baek, Hyung-Yeop
    • International Commerce and Information Review
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    • v.13 no.1
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    • pp.145-175
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    • 2011
  • This paper suggests the strategy for attracting FDI in Gwangju and Jeonnam region using the secondary data collected by homepage of Ministry of Knowledge Economy, Gwangju City, and Jeollanam-do. The strategy for attracting FDI in Gwangju and Jeonnam region is as follows: First, the local governments of Gwangju and Jeonnam must progressively attract FDI by adjusting to the Korean government's regional industry policy direction. Second, in order to attract FDI consistently, the local governments of Gwangju and Jeonnam must enhance the ability of local officials to attract FDI. Third, in order to attract FDI effectively, the local governments of Gwangju and Jeonnam must build a complete system to support FDI. Fourth, in order to attract FDI effectively, the local governments of Gwangju and Jeonnam have to apply different investment incentives according to FDI effectiveness. Fifth, the local governments of Gwangju and Jeonnam must consistently support foreign companies in order to induce FDI expansion by foreign companies which have already invested in the Gwangju and Jeonnam regions. Finally, in order to attract FDI consistently, the local governments of Gwangju and Jeonnam must improve the negative images and living environments of the Gwangju and Jeonnam regions.

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A Study on the Job Stress and Job Satisfaction of Call Center Employees (콜센터 종사자의 직무스트레스와 직무만족도에 관한 연구)

  • Shin, Hye-Young;Kim, Oh-Woo
    • Journal of Distribution Science
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    • v.14 no.5
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    • pp.91-96
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    • 2016
  • Purpose - Although various studies have been conducted on the stress of service employees, there are still lack of studies regarding job stress and job satisfaction of call center workers. Especially there are quite few studies on the job stress according to employment type. This study focused on job stress and job satisfaction for call center employees and the correlation between the two factors and aimed to provide basic materials for seeking for the plans to reduce job stress and improve job satisfaction. Research design, data, and methodology - Frequency, percentage, and mean value were calculated through descriptive statistics in order to find out demographic characteristics, level of job stress, and job satisfaction. Differences in job stress according to employment type were calculated by using one-way ANOVA. Correlation between job stress and job satisfaction were identified through empirical analysis with Pearson's correlation coefficient. 150 materials were used for final analysis. The collected materials were analyzed to get statistics by using SPSS 20. Results - First, as for the job stress of call center workers, overall mean value was 2.54 in 4-point scales. Among the six sub-factors, job demands had the highest score, which was 2.67. Second, as for the job stress according to employment type, others showed higher score than mean value followed by contract job and full-time job in that order, in terms of job insecurity and organizational system. In terms of inappropriate remuneration, contract job showed higher score than mean value followed by others and full-time job. Third, as for the satisfaction with job, the mean value was 2.37 in 4-point scale and "very much satisfied" was only 3.3%. Lastly, in terms of job stress and job satisfaction, all sub-factors except for job demands showed significant correlation. The more job stress increased, the more job satisfaction decreased. Conclusions - First, as a result of analyzing job stress according to the employment type of call center workers, job stress increased more when the employment type was not full-time. Therefore, it was assumed that self-rescue efforts should be followed for effective employment management of call center business where contract employment takes most part as well as efforts to transfer them to full-time job. Second, decrease in job satisfaction of call center workers may affect the performance of an organization as well as service quality of the company providing the service. Therefore, various supports are required to decrease job stress and increase job satisfaction for call center workers through the expansion of rest area or break time. Third, I could recognize that there were lack of academic research on call center business in the whole service industry. Therefore, further research should be conducted more actively in the future. In particular, this study has special significance in the aspect that there were few studies on the job stress of call center workers according to employment type.

Utilization Patterns and Determinants of Oriental Medical Services : Focused on the Residents of Taegu City (한방의료의 이용행태 및 이용결정요인 분석 - 일부 대도시 지역주민을 중심으로 -)

  • Yoo Wang-Keun;Ryu Kyung-A
    • Journal of Society of Preventive Korean Medicine
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    • v.4 no.2
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    • pp.1-24
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    • 2000
  • This study was conducted to examine utilization patterns and determinants of oriental medical services. Data were collected from 545 residents in Taegu city The results of this study are summarized as follows 1) 37.8% of subjects used oriental medical services in the past year. Especially, the female, the ages of 50 and 60 over, the single. low-educated. high-income class, white-collar class, medical insured tended to use more oriental medical services than another groups. 2) 46.7% of users of oriental medical services reported that number of visits in the past year was 2 - 5 times 37 1% of them was 1 times, and 4.5% over 10 times. 3) According to the reasons to choose the oriental medical facilities, most was 'on their own judgement'(48.8%) and 'by the advice of relatives and friends'(42.0%) Regarding to the objectives of using oriental medicine, 68.3% was 'treatment', 31.7% 'health counselling and promotion'. And among diseases of users, diseases of musculo-skeletal system was the highest(54.5%). 4) 57.9% of oriental medical services users had experience of utilizing western medicine on the same diseases. Among peoples with experiencing western medicine on the same diseases. 54.4% received oriental medical services 'in addition to western medicine', 45.6%'in place of western medicine 'And 41.2% of using both services reported that they had difficulty in deciding to choose the type of services -oriental medical services or western medicine-for their diseases. 37.3% of them answered that 'providing relevant information' was the most desirable measure to solve this problem, 27.3% 'establishment of effective referral system between oriental and western medical facilities '23.6% 'cooperative medical treatment systems in the same facilities', 11.8%'integration of oriental medicine into western medicine 5) According to the satisfaction level with each items of oriental medical services, the respondents had positive views on efficacy, kindness, and side-effects. They, however, had negative view on the cost of oriental medical services. 6) In regarding to the priority of improvement of oriental medical system,'expansion of insurance benefit package 'ranked first. 'expansion of insurance benefit Package 'ranked second, 'improvement of scientific methods and diagnostic technique 'third, and 'safety of herbal medicine' fourth in order. 7) The significant factors influencing the utilization of oriental medical services were kindness of oriental medical practitioners, efficacy , travel time, age To be brief, utilization rate of oriental medical services in urban area generally tends to be high. There, however, have been various barriers to limit oriental medical services, such as incomplete benefit package of oriental medical insurance and lack of coordination and referral system between oriental and western medical services, lack of scientific diagnostic procedures, high price etc . For the development of oriental medical services, Much attention to remove these limiting factors should be placed. In addition, kindness of oriental medical practitioners , which is expected to be more important factor in the consumer - focused health care environment than ever, should be kept high consistently. Since this study was conducted for specific residents of an urban city. further research including more sampling in different urban areas should be required to generalize the results of the study.

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Application of HSPF Model for Effect Analyses of Watershed Management Plans on Receiving Water Qualities (유역관리에 따른 수질개선 효과분석을 위한 HSPF 모델 적용)

  • Song, Hye-Won;Lee, Hye-Won;Choi, Jung-Hyun;Park, Seok-Soon
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.5
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    • pp.358-363
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    • 2009
  • The HSPF (Hydrological Simulation Program-Fortran) model was applied to the Kyoungan stream watershed to analyze effects of watershed management plans on receiving water qualities. Utilizing BASINS 3.1 GIS program, the Kyoungan stream watershed was divided into 57 sub-basins and model input parameters were obtained, from DEM (Digital Elevation Model), land use type, stream map, and wastewater treatment facilities, etc.. The hydrologic module of the model was validated based on the measured meteorological data and stream flow data. Then the model was calibrated and verified against the field measurements of water qualities, including temperature, DO, BOD, $NO_3-N$, $NH_3-N$, Org-N, TN and TP. In most cases, there were reasonable agreements between measurements and predictions. The validated model was used to analyze the water quality improvements in the main stream of Kyoungan stream according to the watershed management plans in sub-basins, which are three different scenarios: water quality improvement in tributaries through watershed management activities, expansion and up-grade of wastewater treatment plants, and application of first and second scenarios together. It was concluded that expansion and upgrade of wastewater treatment plants would be more effective than watershed management activities. In order to improve water qualities to the satisfactory level, both watershed management and point source control must be required in the Kyoungan stream.