• Journal of agricultural medicine and community health
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• v.47 no.2
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• pp.61-66
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• 2022

Objectives: In the epidemiology of communicable diseases, the term epidemic period, also referred to as "wave" is often used in the general and academic milieu. A wave refers to a natural pattern of increase in the number of sick individuals, a defined peak, and then a decline in the number of cases. It implies a pattern of peaks and valleys after a particular peak is taken. The idea of epidemic waves is a useful tool for predicting the course as well as helping to accurately describe an epidemic. However, in many domestic and foreign news as well as in various research results in Korea, most of the reports either had no standard, were inaccurate, had a questionable classification of the period of the epidemic, or the basis for classification of a given wave was not presented. Methods: The author reviewed and organized related literature with epidemic wave. The author made several suggestions of an epidemic wave as follows. Results: To start with, it should be based on the number of incident cases in consideration of the size of the outbreak, then the period from the bottom to the peak and then reaching the next bottom; also, the period over a certain scale based on the number of incident cases; and the period according to the change in the major infection type (mutation-dominant species). In addition, according to the period of change in the vaccination rate (formation of herd immunity), as well as the content and duration of the intervention, that is, classification according to the applied quarantine stage. Furthermore, the classification of epidemic periods by the time-dependent reproduction number or time-varying reproduction number (Rt), and lastly the application of mathematical methodology. Conclusions: Therefore, classifying the epidemic period into generally known and accepted time frames is considered to be a very important task for future research analysis and development of intervention strategies.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.11
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• pp.440-446
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• 1984

This thesis investigates the quantitative aspect of epidemic phenomena utilizing the analytical method of discrete time systems based on the theory of Markov processes. In particular, the pattern on the epidemic character of Influenza was analyzed by the mathematical model of Influenza system, which is derived according to the ecologic relationship between five epidemiolgic states of individuals. The quantitative aspects of the model was characterized by digital computer simulations. The main results were obtained as follows: 1) A Markovian model of influenza system represents accurate spead curve. 2) The latent period of influenza has the standard deviation of 1.98 and also the incubation period is 2.68. 3) If the value of susceptibilities in the pre-epidemic period is less than 20% of the population, the epidemic will occur sporadically. 4) The initial value of susceptibilties obtained by this markov theory is less about 10% of total population than the obtained value according to the deterministic model.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1089-1099
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• 2010

An SIR epidemic model with pulse vaccination and time delay describing infection period is investigated. The global attractiveness of the infection-free periodic solution is discussed, and sufficient condition is obtained for the permanence of the system. Our results indicate that a large vaccination rate or a short period of pulsing leads to the eradication of the disease.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.353-362
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• 2018

The national loss caused by the periodic livestock epidemic is very large. In addition, vehicle movement is the main cause of livestock epidemics in Korea. In this context, this study analyzed the relationship between the degree centrality of livestock facilities and the outbreak of infectious diseases. For this purpose, a livestock vehicle movement network was constructed using the facility entrance data provided by KAHIS. Afterwards, the centrality index was derived for each facility in the vehicle movement network and the mean centrality index of the epidemic and non-epidemic facilities were compared. The analysis results are summarized as follows. First, the degree centrality of epidemic facilities is significantly greater than non-epidemic facilities. As a result of the analysis of the entire period data and the period-based data, in most data, the degree centrality of facilities where livestock infectious diseases occurred was significantly greater than most non-occurrence facilities. Second, in the entire period data, the difference in degree centrality between the epidemic and non-epidemic facilities was smaller for HPAI than for FMD. On the other hand, no significant difference was found in the results of the analysis according to the divided period. The policy implications of the results are as follows. First, proactive management of facilities based on centrality is needed. Second, in the case of cloven-hoofed animal facilities, it is more urgent to introduce a management policy based on the degree centrality.

• Parasites, Hosts and Diseases
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• v.39 no.3
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• pp.223-226
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• 2001

In South Korea, the north border area has been under vivax malaria epidemic since 1993. However, Jeollabuk-do, which is about 300 kms from the border, has not experienced the same epidemic. 1 investigated a total of 58 notified cases of malaria in Jeollabuk-do in the year 2000. All of the cases had an exposure history in the epidemic area. Among them were 49 ex-soldiers, 3 soldiers who served near the border area and 6 civilians who traveled there. The causal agent of all cases was Plasmodium vivax. Except the civilians, the soldiers and ex-soldiers were aged in their twenty's. In the present study, the incubation period was from 6 to 520 days with a median of 157 days, and the latent onset type (92%) was more prevalent than the early onset type. illness onset of most cases (86%) peaked during the summer season (June to September) despite of variable incubation periods. The time lag for diagnosis ranged from 2 to 42 days with a median of 11 days. Jeollabuk-do has not been an area of epidemic untill now, but incidences have been increasing annually since 1996. In Jeollabuk-do, early diagnosis and treatment can be a feasible disease control measure to prevent spreading from the epidemic area.

• Advances in Computational Design
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• v.7 no.4
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• pp.345-369
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• 2022

Infectious disease emergency hospitals are usually temporarily built during the pneumonia epidemic with higher requirements regarding diagnosis and treatment efficiency, hygiene and safety, and infection control.This study aims to identify how the Building Information Modeling (BIM) + Industrialized Building System (IBS) approach could rapidly deliver an infectious disease hospital and develop site epidemic spreading algorithms. Coronavirus-19 pneumonia construction site spreading algorithm model mind map and block diagram of the construction site epidemic spreading algorithm model were developed. BIM+IBS approach could maximize the repetition of reinforced components and reduce the number of particular components. Huoshenshan Hospital adopted IBS and BIM in the construction, which reduced the workload of on-site operations and avoided later rectification. BIM+IBS integrated information on building materials, building planning, building participants, and construction machinery, and realized construction visualization control and parametric design. The delivery of Huoshenshan Hospital was during the most critical period of the Coronavirus-19 pneumonia epidemic. The development of a construction site epidemic spreading algorithm provided theoretical and numerical support for prevention. The agent-based analysis on hospital evacuation observed "arched" congestion formed at the evacuation exit, indicating behavioral blindness caused by fear in emergencies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.97-107
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• 1990

The epidemiology of plant disease deals with the dynamic processes of host-pathogen interactions, which determine the prevalence and severity of the disease. Epidemic processes for most foliar diseases of plants follow a series of steps: arrival of pathogens on plant surfaces, initial infection, incubation period, latent period, sporulation, dissemination of secondary inoculum, and infectious period. These complex biological processes are influenced by the environment-Man also often interfers with these processes by altering the host and pathogen populations and the environment. Slowing or halting any of the epidemic processes can delay the development of the epidemic, so that serious losses in yield due to disease do not occur. It is generally recognized that the most effective and efficient method of minimizing disease damage is through the use of resistant cultivars, particularly when other methods such as fungicide applications are not economically feasible-Populations of plant pathogens are not genetically uniform nor are they necessarily stable. Cultivars bred for resistance to current populations of a pathogen may not be resistant in the future due to selection pressures placed on the pathogen populations. Understanding population development and genetic variability in the pathogen, and knowledge of the genetics of resistance in the plant should help in developing breeding strategies that wi1l provide effective and stable disease control through genetic resistance. In the United States, soybeans have ranked first in value of crops sold off the farm in recent years. Soybeans have been the leading U. S.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.818-822
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• 1998

The persistence of porcine epidemic diarrhea virus(PEDV) infection was demonstrated in 7 swine farms employing continuous pig flow management even after seasonal outbreaks. Clinically, sporadic postweaning diarrhea was a major concern in those farms. Subsequently circulatory antibody detection using serum neutralizing test made useful for confirmation of PEDV persistent infections. The persistence of PEDV in the premise might have induced recurrence over the period of time.

• Journal of Korean Medical classics
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• v.20 no.4
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• pp.251-265
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• 2007

This study is a research on the etiology in Wu Youke's wenyi theory. In regard to the etiology of epidemic disease that had been spread on a very large scale at that time, Wu Youke denied the traditional theory which urged the irregular change of climate as the cause of epidemic disease, and proposed the concept of 'zaqi' which was considered by him to be something that could be the real cause of epidemic disease. And He treated the wenyi disease as something that has the same meaning with wenbing, so his concept on wenbing was basically the thing that treats 'zaqi' as the fundamental cause of wenbing and treats the concept of 'wen(溫)' as an environmental cause that could help activate the virulence of 'zaqi'. Such concept like this was the thing somewhat different from the traditional etiological theory that considers the change of climate as the principal cause of waigan(外感)-disease, and it must for the most part have been originated from the experience of Wu Youke himself. But this study, in contrast, based on the thing he denied the traditional theory on the irregular change of climate, has been done in the point of view that fundamental concept of his wenyi theory such as 'zaqi' was not only originated from his clinical experience but also from the influence of paradigm shift in the natural philosophy of that time. There had been so much change in cosmology and natural philosophy from the fundamental basis at that time, and the the most principal concept of it was that there always exists irregular faces in the change of nature. Such concept like this got into its stride from about 17th century, and it was expressed in the form of the severe criticism against the traditional natural philosophy. In regard to this, this study has outlined the academic thought of the leading scholars who made a significant progress in such a paradigm shift, and it includes the scholars like Wang Tingxiang, Wang Fuzhi, Hu Wei, Huang Zongxi, who played their role in the time of the latter period of Ming dynasty and the former period of Qing dynasty.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.295-304
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• 1994

This paper describes some preliminary attempts to formulate simple mathematical models of the transmission dynamics of HIV infection in homosexual communities. In conjunction with a survey of the available epidemiological data on HIV infection and the incidence of AIDS, the model is used to assess how various processes influence the course of the initial epidemic following the introduction of the virus. Models of the early stages of viral spread provide crude methods for estimating the basic reproductive rate of the virus, given a knowledge of the incubation period of AIDS and the initial doubling time of the epidemic. More complex models are formulated to assess the influence of heterogeneity in sexual activity. This latter factor is shown to have a major effect on the predicted pattern of the epidemic.