• Title/Summary/Keyword: Condition-Based-Maintenance

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Correction of Latent Errors in Pavement Deterioration Data using Statistical Methods (통계기법을 활용한 포장파손자료의 잠재오차 보정)

  • Han, Daeseok;Do, Myungsik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6D
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    • pp.587-598
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    • 2012
  • Successful implementation of infrastructure asset management system can be started with rich and reliable data. However, measurement errors in the data have always existed in the real world caused for many unknown reasons. It disturbs maintenance activities of agencies, and makes negative effects to reliability of research results on forecasting deterioration process and life cycle cost. Above all, it makes a contradiction that road agencies cannot believe their inspection data surveyed by their hands. It is particularly serious in the road pavement management field. Although road agencies are well recognized the fact, inspecting without measurement error would be a great challenge. Considering the facts, this paper aimed to suggest statistical error processing methods to correct latent error included in pavement surface inspection data. As alternatives, this paper suggested two methods based on probability distribution to consider structure of error and reliability of the data. The suggested methods were empirically tested by using pavement inspection data from Korean National Highway. As the result, this paper confirmed that conventional error processing that just removes only visible errors is not enough to cover uncertainty in pavement deterioration process. The suggested methods would be useful for improving reliability of analysis results required for road infrastructure asset management.

Reuse Technology Development and Economic Evaluation of Dyeing Wastewater Treatment Sludge (폐수처리슬러지의 재활용기술개발 및 경제성 평가 -B염색조합을 중심으로-)

  • 임재호;이정연
    • Resources Recycling
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    • v.9 no.1
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    • pp.36-43
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    • 2000
  • This study was carried out for treatment and reuse of inorganic sludge from Fenton process at B dyeing wastewater treatment plant. The parameters for pilot-scale treatment system were derived from the results of this study. It was found that $COD_{cl}$ of the treated effluent became lower than 100 mg/l approximately on the optimal reaction condition. 2nd sludge which was generated after redissolving sludge was analyzed, and it showed that reduction ratio of ash in 2nd sludge and total dry sludge weight in comparison with current sludge were 85% and 65%. Also Fe salt in sludge was redissolved about 90~95% of initial Fe by weight. It was estimated almost ₩350,000,000 for sludge reuse process. It was estimated saving of about ₩1,300,000 per day (₩420,000,000 per year) in operating cost based on 30,000 $m^3$/d treatment, which these were about ₩430,000 per day in chemical, ₩1,100,000 per day in sludge transportation and ₩200,000 per day in equipment maintenance. Payback period with interest charge for investment cost was estimated about 10.5 months. Also, net present value (NPV) was ₩792,000,000 and internal rat of return (IRR) was about 110%.

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Classification of Recreation Forests through Cluster Analysis (군집분석을 통한 전국 자연휴양림 유형분류)

  • Lee, Kee-Cheol;Kang, Kee-Rae
    • Journal of the Korean Institute of Landscape Architecture
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    • v.37 no.1
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    • pp.9-17
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    • 2009
  • Twenty years have passed since the adoption of natural recreation forests and each forest has its own characteristics. However, there is hardly any classification among the natural recreation forests. The purpose of this study is to classify the forests by considering the supplier's perspective as well as the user's perspective in order to provide fundamental materials for the operation of the natural recreation forests. A factor analysis was conducted to identify the common characteristics of the selected twelve variables by pre-selection and survey of experts. K-means cluster analysis was conducted among those factors to classify the natural recreation forests in Korea. Four factors were drawn after the factor analysis and the factors were named according to the variables and sizes as 'The use performance and visiting condition factor', 'Education and settlement factor', 'Internal activation factor' and 'Potential factor' In addition, the cluster analysis of an $85{\times}4$ matrix was conducted for the points of the drawn factors and the final classification consists of five groups. The results of this study may contribute to providing fundamental materials for the operation and management of natural recreation forests. Also, it may act as a reference when investigating the natural recreation forests of Korea. Proposing the classification natural recreation forests could be helpful in selecting the proper recreation forest in the future. Based on the established model, fundamental materials could be provided to improve the profitability of the natural recreation forests by effectively expanding the number of tourists, creating new natural recreation forests and proper maintenance and management.

Lifetime test of batteries for BLE modules for site identification of vessel's crews and passengers (SIVCP) (SIVCP용 BLE 모듈의 배터리 수명시험)

  • Kwon, Hyuk-joo;Kim, Min-Gwon;Kim, Yoon-Sik;Lee, Sung-Geun
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.7
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    • pp.754-759
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    • 2015
  • Nowadays, short distance communication systems with low power energy (LPE) are developed for identification and monitoring of site identification of vessel crews and passengers (SIVCP). LPE communication modules, such as Bluetooth low energy (BLE) and Zigbee, are used for short distance communications with LPE. These modules enable 1:N communications and their popularity is growing since the modules can be mounted on movable objects, such as mobile devices and human body. When these modules are used, the important factor that affects their operation time and design are the capacity and size of battery. Therefore, they must be made as small as possible, and the battery should be selected to be slightly smaller than the module. In this study, we calculate the theoretical life of batteries used in SIVCP BLE modules using data sheet and discharge characteristic graph under the condition of a 1/250 transmission-ratio (TR). We thus calculate experimental life by measuring transmission current for the same TR, and low speed mode current for a 1/5000 TR and measure long-term experimental life using 1/25 TR for days. Through these experiments, we verify experimental methods for the prediction and extension of battery life that would enable us to select appropriate sizes of batteries based on vessel usage and passenger types. The selections of the module TR and battery size are important factors affecting the cost reduction of module design, the battery maintenance, and passenger convenience.

A Grounded Theory Approach to the Comfort Experience of Hospitalized Patients (입원대상자의 안위경험에 대한 근거이론적 접근)

  • 김경희;김금순;강규숙;강현숙;김원옥;백훈정;원종순;임난영;정인숙
    • Journal of Korean Academy of Nursing
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    • v.30 no.3
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    • pp.750-763
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    • 2000
  • This study is based on grounded theory methodology by Strauss & Corbin(1998). Ten hospitalized subjects were interviewed for data collection. In the process of data analysis, 'acceptance' is found to be the causal condition, while 'health professionals' skillfulness', 'ward environment', 'history of hospitalization', and 'general conditions' were identified as context, 'felling of relief' as the core phenomenon, 'self-efficacy', 'support of others', and 'life style' as the intermediate situation, 'passive reaction', 'alternative reaction' and 'active reaction' as the strategy and 'stabilization', 'satisfaction', 'hope' and 'carrying out' as consequences. 'Feeling of relief' is found to go through the three stages of recognition-generation-maintenance after the five different patterns. 1) In case the health professionals are skillful, the ward environment is favorable, the general conditions of the patients improved and as a result the feeling of relief is strong, during the first hospitalization, the self-efficacy of the subjects tends to be strong. They proceed toward the goal set for themselves with a renewed hope and active or alternative reaction toward the feeling of relief. 2) The subjects tend to proceed toward the goal set for themselves with a renewed hope and active and alternative reaction toward the feeling of relief in case health professionals are skillful, the ward environment is favorable the general conditions of the subjects improved, self-efficacy is strong, and lifestyle is autonomous, during the second hospitalization even though support of others is merely superficial. 3) The subjects tend to stabilize, and satisfy themselves with the given situation with passive and alternative reaction to the feeling of relief in case health professionals are skillful and the ward environment is favorable but the general conditions worsened and accordingly the feeling of relief, is weak and life style is dependent during the second hospitalization although the subjects' self-efficacy is strong and support of others is specific. 4) The subjects tend to stabilize and satisfy themselves with the given situation with passive and alternative reaction to the feeling of relief in case health professionals are unskillful the ward environment is unfavorable, the general conditions improved, support of others is specific but life style is dependent and self-efficacy is weak during the first hospitalization. 5) The subjects tend to stabilize and satisfy themselves with the given situation in case health professionals are unskillful the ward environment is unfavorable but the general conditions improved support of others is specific and as a result self-efficacy is strong but life style is dependent.

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Measures to Implements the Landscape Conservation and Management in the Seowon Hamyang Namgye inscribed on the World Heritage List (세계유산 등재대상 함양 남계서원의 경관보존관리방안)

  • Choi, Jong-Hee;Moon, Young-Suk;Kim, Dong-Hyun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.31 no.2
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    • pp.128-135
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    • 2013
  • The purpose of this study is a suggestion that it is a way for conservation and management the Namgye Seowon's heritage value based on its landscape visibility and land use; Namgye Seowon is a world heritage registration object. To do this, We had done a field investigation and a literature examination. The investigations are as following; first, setting protection zone through a comprehensive approach beyond uniform cultural properties protection zone is to note current intellectual situations as well as the place related to the locational characteristics and figures of Namgye Seowon. It's to set fore seeable section of landscape by analyzing visibility focusing through on Pungyeongnu, and it consider with protection zone and the present condition of land use. Especially, external view of landscape in Namgye Seowon is visualized with Baekam-san in the distance view of it and Cheonhwang-bong in Daebong-san and nearby large soundproof walls and the towers acts as an impediment factor to the view of landscape. In addition, to recover the original view of landscape of the Namgye Seowon, reckless plans focusing the authenticity of the world heritage should be limited and in case of the vegetation landscape, restoration and maintenance will be made through historical research literature. Through this study, researches on Namgye Seowon and several seowons will be done actively and its aims are to become the framework of landscape conservation and management measures to meet world heritage criteria.

An Analytical Solution of Dynamic Responses for Seabed under Coexisting Fields of Flow and Partial Standing Wave with Arbitrary Reflection Ratio (흐름과 임의반사율을 갖는 부분중복파와의 공존장하에서 해저지반내 동적응답의 해석해)

  • Lee, Kwang-Ho;Kim, Dong-Wook;Kang, Gi-Chun;Kim, Do-Sam;Kim, Tae-Hyung;Na, Seung-Min
    • Journal of the Korean Geotechnical Society
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    • v.31 no.6
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    • pp.27-44
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    • 2015
  • An analytical solution of dynamic responses for seabed in finite and infinite thicknesses including shallow has been developed under flow and partial standing wave with arbitrary reflection ration coexisting field at a constant water depth condition. In the analytical solution, a field was simply transited to a coexisting field of progressive wave and flow when reflection ratio was 0 and to a coexisting field of fully standing wave and flow when reflection ratio was 1. Based on the Biot's consolidation theory, the seabed was assumed as a porous elastic media with the assumptions that pore fluid is compressible and Darcy law governs the flow. The developed analytical solution was compared with the existing results and was verified. Using the analytical solution the deformation, pore pressure, effective and shear stresses were examined under various given values of reflection ratio, flow velocity, incident wave's period and seabed thickness. From this study, it was confirmed that the dynamic response of seabed was quite different depending on consideration of flow, which causes changing period and length of incident and reflection waves. It was also confirmed that dynamic response significantly depends on the magnitude of reflection ratio.

A survey of the status of hair loss product use, hair loss treatment and satisfaction level (탈모(脫毛) 고객(顧客)의 제품이용실태와(製品使用實態) 관리(管理) 및 만족도(滿足度) 조사(調査))

  • Lee, Ji-Suk;Kim, Sung-Nam
    • Journal of Fashion Business
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    • v.11 no.2
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    • pp.76-91
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    • 2007
  • The domestic market for scalp care and hair loss management reached 1 trillion won. The market for hair loss management is expected to expand further. Systematic scalp and hair care services, such as scalp scaling, scalp massage, equipment maintenance, scalp care products sale, and care program based on scalp and trichology are provided. This study examined the status of hair loss management and use of hair care products by people experiencing hair loss and the level of their satisfaction. In addition, this study presents basic data for the effective hair loss management and marketing strategies for scalp and hair loss clinics. The results are as follows. 41.2% of the study subjects were in their 20s, and 66.6% of the study subjects were women. As for the hair loss symptoms, 45.2%, the largest percentage, had thin and wispy hair and more women had thin hair than men. 80.0% of men had oily hair. As for the scalp condition, 39,3% had oily scalp. As more women experience hair loss, 39.6% had female pattern hair loss and 31.0% had male pattern hair loss. As the largest percentage of people experiencing hair loss was in their 20s, 33.4%, the largest percentage, had the onset of hair loss in their early 20s. 34.1%, the largest percentage, reported having used the clinic for less than 1 month. The older the subject, the longer the length of hair clinic use. As for the average number of monthly hair loss clinic visits, 28.2%, the largest percentage, said 3 times. As for the hair loss management product use, 61.9%, said they do not use it and 38.1% said they use it. 5.6%, the largest percentage, used Davines at home and 9.6%, the largest percentage, used Kerastase at the clinic. As for the experience of hair loss product previously, 84.5% said they had no experience and 15.5% said they had eThe following are related to the satisfaction level of hair loss management. xperience. 5.0%, the largest percentage, reported having used Daenggimeori. The following are related to the satisfaction level of hair loss management. 32.8%, the largest percentage, said the effect of hair loss management lasted less than 6 monthas. As for the satisfaction levels on hair loss management program, service, skill of the hair specialist, hygiene, and hair loss management products, most people indicated between average and somewhat satisfactory levels. As for the satisfaction level on the cost of hair loss management, most people indicated average satisfaction level. As for the element essential to hair loss management, 39.0%, the largest percentage, indicated development of effective and specialized programs, 28.2%, indicated low price, 25.1%, indicated systematic and professional education of the hair specialist, 4.6%, indicated marketing and promotion, 2.5%, indicated service quality, and 0.6% indicated others.

Effects of Feeding Rate and Frequency on the Winter Growth and Body Composition of Olive Flounder, Paralichthys olivaceus (배합사료 공급율 및 공급횟수가 겨울철에 사육된 육성기 넙치의 성장 및 체조성에 미치는 영향)

  • Kim, Kyoung-Duck;Nam, Myung-Mo;Kim, Kang-Woong;Kim, Dong-Gyu;Son, Maeng-Hyun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.3
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    • pp.217-222
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    • 2010
  • Two 15-week feeding trials were conducted to investigate how the rate and frequency of feeding affected the winter growth of olive flounder ($13^{\circ}C$). In the first experiment, triplicate groups of fish (initial mean weight $117{\pm}6.0$ g) were fed extruded pellets twice a day at feeding rates of 0.1, 0.25, 0.4, 0.55, and 0.57% (satiation) body weight per day (BW/d). The weight gain, specific growth rate, and feed efficiency increased significantly (P<0.05) with the feeding rates from 0.1 to 0.55% BW/d, but no significant differences in these parameters were found for fish fed diets of 0.55% BW/d and satiation. The moisture and ash contents of whole body of fish tended to decrease as the feeding rate increased, but the opposite trend was found for crude lipid content. In the second experiment, triplicate groups of fish (initial mean weight $117{\pm}6.3$ g) were fed extruded pellets to apparent satiation at the three different feeding frequencies: one meal 2 days, one meal a day and two meals a day. The weight gain and specific growth rate of fish fed one meal 2 days were significantly (P<0.05) lower than those of fish fed one or two meals a day, whereas no significant differences in the weight gain and specific growth rate were found between fish fed one and those fed two meals a day. Feed efficiency and condition factor were not significantly affected by feeding frequency. Based on these results, a feeding rate of 0.3% BW/d is recommended as maintenance feeding level, and the optimum feeding frequency is one meal a day with satiation feeding for the growth of olive flounder (117-147 g) during winter ($13^{\circ}C$).

The Performance of Pollutant Removal Using Nonpoint Treatment Filtration Device and Analysis of the Filter Backwashing Effect (여과형 비점오염 처리장치의 오염물질 제거특성 및 역세척 분석)

  • Lee, Jun-ho;Yang, Seung-ho;Bang, Ki-woong
    • Journal of Korean Society on Water Environment
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    • v.31 no.5
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    • pp.523-532
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    • 2015
  • Hydrocyclone is widely used in industry, for its simple design, high capacity, low maintenance and low operational cost. The objective of this study is to develop hydrocyclone coagulation and filtration system. The system is made of hydrocyclone ballasted coagulation with polyaluminium chloride silicate (PACS) and upflow filter to treat micro particles in urban storm runoff. Roadside sediment particles (< $200{\mu}m$) was mixed with tap water to make various turbid suspensions to simulate urban storm runoff. The filter cartridge was filled with polyethylene media system and ran 1hr per everyday and total operation time were 8.19hrs and backwashing everyday after end of operation. The operation condition of flowrate was $8.2{\sim}11.9m^3/day$ (mean $10.1m^3/day$) and surface overflow rate (SOR) based on filter surface area was $45.5{\sim}65.9m^3/m^2/day$ (mean $55.7m^3/m^2/day$). The range of PACS dosage concentration was 14.0~31.5 mg/L. As the results of operation, the range of removal efficiency of turbidity, SS were 81.0~95.8% (mean 89.5%) 81.8~99.0% (mean 91.4%), respectively. An increase of filtration basin retention time brought on increased of removal efficiency of turbidity and SS, and increase of SOR brought on decreased of removal efficiency. During the first flush in urban area, storm runoff have an high concentration of SS (200~600 mg/L) and the filtration bed becomes clogged and decreased of removal efficiency. Backwashing begins when the drainage pipe valve at the filtration tank bottom is completely open (backwashing stage 1). Backwashing stage 2 was using air bubbles and water jet washing the media for 5 mins and open the drainage valve. After backwashing stage 1, 2, 61.83~64.04%, 18.53~27.51% of SS loading was discharged from filtration tank, respectively. Discharged SS loading from effluent was 7.12~14.79% and the range of residual SS loading in fliter was 2.26~5.00%. The backwashing effects for turbidity, SS were 89.5%, 91.4%, respectively. The hydrocyclone coagulation and filtration with backwashing system, which came out to solve the problems of the costly exchange filter media, and low efficiency of removing micro particles of filter type nonpoint treatment devices, is considered as an alternative system.