Development of a Failure Probability Model based on Operation Data of Thermal Piping Network in District Heating System (지역난방 열배관망 운영데이터 기반의 파손확률 모델 개발)
-
- Korean Chemical Engineering Research
- /
- v.55 no.3
- /
- pp.322-331
- /
- 2017
District heating was first introduced in Korea in 1985. As the service life of the underground thermal piping network has increased for more than 30 years, the maintenance of the underground thermal pipe has become an important issue. A variety of complex technologies are required for periodic inspection and operation management for the maintenance of the aged thermal piping network. Especially, it is required to develop a model that can be used for decision making in order to derive optimal maintenance and replacement point from the economic viewpoint in the field. In this study, the analysis was carried out based on the repair history and accident data at the operation of the thermal pipe network of five districts in the Korea District Heating Corporation. A failure probability model was developed by introducing statistical techniques of qualitative analysis and binomial logistic regression analysis. As a result of qualitative analysis of maintenance history and accident data, the most important cause of pipeline damage was construction erosion, corrosion of pipe and bad material accounted for about 82%. In the statistical model analysis, by setting the separation point of the classification to 0.25, the accuracy of the thermal pipe breakage and non-breakage classification improved to 73.5%. In order to establish the failure probability model, the fitness of the model was verified through the Hosmer and Lemeshow test, the independent test of the independent variables, and the Chi-Square test of the model. According to the results of analysis of the risk of thermal pipe network damage, the highest probability of failure was analyzed as the thermal pipeline constructed by the F construction company in the reducer pipe of less than 250mm, which is more than 10 years on the Seoul area motorway in winter. The results of this study can be used to prioritize maintenance, preventive inspection, and replacement of thermal piping systems. In addition, it will be possible to reduce the frequency of thermal pipeline damage and to use it more aggressively to manage thermal piping network by establishing and coping with accident prevention plan in advance such as inspection and maintenance.
The categories of national health problems may be mainly divided into health promotion, problems of diseases, and population-economic problems which are indirectly related to health. Of them, the problems of diseases will be exclusively dealt with this speech. Rurality and Disease Problems There are many differences between rural and urban areas. In general, indicators of rurality are small size of towns, dispersion of the population, remoteness from urban centers, inadequacy of public transportation, poor communication, inadequate sanitation, poor housing, poverty, little education lack of health personnels and facilities, and in-accessibility to health services. The influence of such conditions creates, directly or indirectly, many problems of diseases in the rural areas. Those art the occurrence of preventable diseases, deterioration and prolongation of illness due to loss of chance to get early treatment, decreased or prolonged labour force loss, unnecessary death, doubling of medical cost, and economic loss. Some Considerations of Innovative Approach The followings art some considerations of innovative approaches to the problems of diseases in the rural Korea. 1. It would be essential goal of the innovative approaches that the damage and economic loss due to diseases will be maintained to minimum level by minimizing the absolute amount of the diseases, and by moderating the fee for medical cares. The goal of the minimization of the disease amount may be achieved by preventive services and early treatment, and the goal of moderating the medical fee may be achieved by lowering the prime cost and by adjusting the medical fees to reasonable level. 2. Community health service or community medicine will be adopted as a innovative means to disease problems. In this case, a community is defined as an unit area where supply and utilization of primary service activities can be accomplished within a day. The essential nature o the community health service should be such activities as health promotion, preventive measures, medical care, and rehabilitation performing efficiently through the organized efforts of the residents in a community. Each service activity should cover all members of the residents in a community in its plan and performance. The cooperation of the community peoples in one of the essential elements for success of the service program, The motivations of their cooperative mood may be activated through several ways: when the participation of the residents in service program of especially the direct participation of organized cooperation of the area leaders art achieved through a means of health education: when the residents get actual experience of having received the benefit of good quality services; and when the health personnels being armed with an idealism that they art working in the areas to help health problems of the residents, maintain good human relationships with them. For the success of a community health service program, a personnel who is in charge of leadership and has an able, a sincere and a steady characters seems to be required in a community. The government should lead and support the community health service programs of the nation under the basis of results appeared in the demonstrative programs so as to be carried out the programs efficiently. Moss of the health problems may be treated properly in the community levels through suitable community health service programs but there might be some problems which art beyond their abilities to be dealt with. To solve such problems each community health service program should be under the referral systems which are connected with health centers, hospitals, and so forth. 3. An approach should be intensively groped to have a physician in each community. The shortage of physicians in rural areas is world-wide problem and so is the Korean situation. In the past the government has initiated a system of area-limited physician, coercion, and a small scale of scholarship program with unsatisfactory results. But there might be ways of achieving the goal by intervice, broadened, and continuous approaches. There will be several ways of approach to motivate the physicians to be settled in a rural community. They are, for examples, to expos the students to the community health service programs during training, to be run community health service programs by every health or medical schools and other main medical facilities, communication activities and advertisement, desire of community peoples to invite a physician, scholarship program, payment of satisfactory level, fulfilment of military obligation in case of a future draft, economic growth and development of rural communities, sufficiency of health and medical facilities, provision of proper medical care system, coercion, and so forth. And, hopefully, more useful reference data on the motivations may be available when a survey be conducted to the physicians who are presently engaging in the rural community levels. 4. In communities where the availability of a physician is difficult, a trial to use physician extenders, under certain conditions, may be considered. The reason is that it would be beneficial for the health of the residents to give them the remedies of primary medical care through the extenders rather than to leave their medical problems out of management. The followings are the conditions to be considered when the physician extenders are used: their positions will be prescribed as a temporary one instead of permanent one so as to allow easy replacement of the position with a physician applicant; the extender will be under periodic direction and supervision of a physician, and also referral channel will be provided: legal constraints will be placed upon the extenders primary care practice, and the physician extenders will used only under the public medical care system. 5. For the balanced health care delivery, a greater investment to the rural areas is needed to compensate weak points of a rurality. The characteristics of a rurality has been already mentioned. The objective of balanced service for rural communities to level up that of urban areas will be hard to achieve without greater efforts and supports. For example, rural communities need mobile powers more than urban areas, communication network is extremely necessary at health delivery facilities in rural areas as well as the need of urban areas, health and medical facilities in rural areas should be provided more substantially than those of urban areas to minimize, in a sense, the amount of patient consultation and request of laboratory specimens through referral system of which procedures are more troublesome in rural areas, and more intensive control measures against communicable diseases are needed in rural areas where greater numbers of cases are occurred under the poor sanitary conditions.
Introduction Recently, changes in the patterns and concepts of maternity care, in both developing and developed countries have been accelerating. An outstanding development in this field is the number of deliveries taking place in hospitals or maternity centers. In Korea, however, more than 90% of deliveries are carried out at home with the help of untrained relatives or even without helpers. It is estimated that less than 10% of deliveries are assisted by professional persons such as a physician or a midwife. Taking into account the shortage of professional person i11 rural Korea, it is difficult to expect widespread prenatal, postnatal, and delivery care by professional persons in the near future, It is unrealistic, therefore, to expect rapid development of MCH care by professional persons in rural Korea due to economic and sociological reasons. Given these conditions. it is reasonable that an educated village women could used as a "maternity aid", serving simple and technically easy roles in the MCH field, if we could give such a women incentive to do so. The midwife and physician are assigned difficult problems in the MCH field which could not be solved by the village worker. However, with the application of the village worker system, we could expect to improve maternal and child hoalth through the replacement of untrained relatives as birth attendants with educated and trained maternity aides. We hope that this system will be a way of improving MCH care, which is only one part of the general health services offered at the local health centre level. Problems of MCH in rural Korea The field of MCH is not only the weakest point in the medical field in our country hut it has also dropped behind other developing countries. Regarding the knowledge about pregnancy and delivery, a large proportion of our respondents reported having only a little knowledge, while 29% reported that they had "sufficient" knowledge. The average number of pregnancies among women residing in rural areas was 4.3 while the rate of women with 5 or more pregnancies among general women and women who terminated childbearing were 43 and 80% respectively. The rate of unwanted pregnancy among general women was 19.7%. The total rate for complications during pregnancy was 15.4%, toxemia being the major complication. The rate of pregnant women with chronic disease was 7%. Regarding the interval of pregnancy, the rates of pregnancy within 12 months and within 36 months after last delivery were 9 and 49% respectively. Induced abortion has been increasing in rural areas, being as high as 30-50% in some locations. The maternal death rate was shown 10 times higher than in developed countries (35/10,000 live births). Prenatal care Most women had no consultation with a physician during the prenatal period. Of those women who did have prenatal care, the majority (63%) received such care only 1 or 2 times throughout the entire period of pregnancy. Also, in 80% of these women the first visit Game after 4 months of gestation. Delivery conditions This field is lagging behind other public health problems in our country. Namely, more than 95% of the women deliveried their baby at home, and delivery attendance by a professional person occurred only 11% of the time. Attendance rate by laymen was 78% while those receiving no care at all was 16%. For instruments used to cut the umbilical corn, sterilized scissors were used by 19%, non-sterilized scissors by 63% and 16% used sickles. Regarding delivery sheets, the rate of use of clean sheets was only 10%, unclean sheets, vinyl and papers 72%, and without sheets, 18%. The main reason for not using a hospital as a place of delivery was that the women felt they did not need it as they had previously experience easy deliveries outside hospitals. Difficult delivery composed about 5% of the total. Child health The main food for infants (95%) was breast milk. Regarding weaning time, the rates within one year, up to one and half, two, three and more than three years were 28,43,60,81 and 91% respectively, and even after the next pregnancy still continued lactation. The vaccination of children is the only service for child health in rural Korea. As shown in the Table, the rates of all kinds of vaccination were very low and insufficient. Infant death rate was 42 per 1,000 live births. Most of the deaths were caused by preventable diseases. Death of infants within the neonatal period was 83% meaning that deaths from communicable diseases decreased remarkably after that time. Infant deaths which occurred without medical care was 52%. Methods of improvement in the MCH field 1. Through the activities of village health workers (VHW) to detect pregnant women by home visiting and. after registration. visiting once a month to observe any abnormalities in pregnant women. If they find warning signs of abnormalities. they refer them to the public health nurse or midwife. Sterilized delivery kits were distributed to the expected mother 2 weeks prior to expected date of delivery by the VHW. If a delivery was expected to be difficult, then the VHW took the mother to a physician or call a physician to help after birth, the VHW visits the mother and baby to confirm health and to recommend the baby be given proper vaccination. 2. Through the midwife or public health nurse (aid nurse) Examination of pregnant women who are referred by the VHW to confirm abnormalities and to treat them. If the midwife or aid nurse could not solve the problems, they refer the pregnant women to the OB-GY specialist. The midwife and PHN will attend in the cases of normal deliveries and they help in the birth. The PHN will conduct vaccination for all infants and children under 5, years old. 3. The Physician will help only in those cases referred to him by the PHN or VHW. However, the physician should examine all pregnant women at least three times during their pregnancy. First, the physician will identify the pregnancy and conduct general physical examination to confirm any chronic disease that might disturb the continuity of the pregnancy. Second, if the pregnant woman shows any abnormalities the physician must examine and treat. Third, at 9 or 10 months of gestation (after sitting of the baby) the physician should examine the position of the fetus and measure the pelvis to recommend institutional delivery of those who are expected to have a difficult delivery. And of course. the medical care of both the mother and the infants are responsible of the physician. Overall, large areas of the field of MCH would be served by the VHW, PHN, or midwife so the physician is needed only as a parttime worker.