Forecasting median and mode dates of prevalence of Japanese encephalitis patients by electronic computer (epidemiological studies on Japanese encephalitis, 31)

For the purpose of forecasting the prevalence ofJapanese encephalitis in Japan, we tried to find out the correlation of factors between median and mode dates of epidemic time curve of prevalence on one hand, and average atmospheric temperatures of prefectures in June and July (T6,7 in short) (X&#185;), the time when HI reaction of swine became positive to the degree of 50 per cent (D. pos. swine in short) (X&#178;), the latitude (x&#179;) and longitude (x4) in respective prefectures (in 1965 and 1967). On the other we also estimated the median and mode dates of this epidemic curve of the prevalence in 1968 and 1969, from the regression equation of one variable and multiple regression equation from the above factors using an electronic computer. The usefulness of adding factors concerned with mosquitoes to the above four factors is proven by the accuracy of estimation. And the following results were obtained. 1) Phenomenally speaking, the prevalence of Japanese encephalitis follows the principle of &#34;advancing of prevalence towards the north and east&#34; and essentially speaking, it depends upon high atmospheric temperature and the outbreak of many hazardous mosquitoes by the high atmospheric temperature. 2) To estimate median date (y) and mode rate (z) of the epidemic time curve of the prevalence, we can use the next equations; The regression equations to estimate y and z from T 6,7(X) are as follows. y = - 3. 75X&#185; + 144.47 &#963; = 12.4.·. [1] z = - 3. 80X&#185; + 157 .26 &#963; = 14.9.. · [1]' The regression equation from D. pos. swine (X&#178;) are as follows. y = 0. 68X&#178; + 31. 82 &#963; = 9.2· .. [2] z=0. 76X&#178; +40. 71 &#963;= 12.0 .. · [2]' The multiple regression equation from T6 ,7 and D. pos. swme are as follows. y = -1. 07X&#185; +0 .62x&#178; +59. 37 &#963;= 9.7 ... [3] z= -0. 79x&#185; +0. 71x&#178; +61.02 &#963;= 12.0· .. [3]' The multiple regression equations from T 6•7, D. pos. swine, latitude and longitude are as follows Y= -1.01x&#185; +0.58x&#178; -0.26x&#179;+0 .37x4 + 18.50 &#963;= 9.8&#65381;&#65381;&#65381; [4] z = -0. 32x&#185; +0. 52x&#178; +2 .05x&#179; +0 .54x4 -87. 81 &#963;= 11.8 [4]' 3) We Obtained the estimated value of median date in 17 prefectures in Kyushu, Chugoku, Shikoku, Kinki and Kanto provinces in 1968 and in 13 prefectures in 1969 from [l] or [2] or [3] or [4] equation. Nine prefectures out of 17 by [l], 12 prefectures by [2], 13 by [3J and [4] in 1968. [4] could be estimated with about 10 days error or less. And in 1969, 9 out of 13 by [3] and 7 out of 13 by [4] could be accurately esti· mated. The estimation by the multiple regression equation using many factors is most useful for the calculation. 4) The time when the number of patients increases at maximum can be pointed out by the lower limit of prediction region obtained from data in each prefecture. And the lower limit was the estimated median value minus about 20 days by [1] and about 16 days by [2] or [3] or [4] under the next condition; &#945; = 0. 1, N= 75. 5) The mode dates in 17 prefectures out of 19 were estimated by [1]', [2]', [3]' and [4]'. 12 prefectures out of 17 by [1]', 7 by [2]', 10 by [3]' and 13 by [4]' could be estimated with about 12 days error or less in 1968 and 9 out of 13 was correctly estimated by [3]' and [4]' in 1969. The estimation by the regression line of one factor was s~mewhat different from each other, but when multiple regression line of four factors was used the estimation became more correct. Judging from these results, it is adequate to use the multiple regression equation of [4] and [4]' when we want to forecast the median date or mode date ofJapanese encephalitis time cure. 6) In the case of adding two factors concerned with mosquitoes to T6,7 (X&#185;), D. pos. swine (x&#178;), latitude (x&#179;), longitude (x4), multiple regression equations become as follows. y= -1.46x&#185;+0.14X&#178;+0.068x5+89.03 &#963;= 6.9.. ·[5] z= -3. 29x&#185;+0 .13x&#178;-0. 010x5+ 143.63 &#963;= 18.6··· [5]' y=-4.20x&#185;+0.35x&#178;+0.29x6 + 53.70 &#963;= 4.2 .. ·[6] z=-2.56x&#185;-0.0lx&#178;-0.02x6 +128.96 &#963;=11.4 [6]' y= 4.76x&#185;+0.41x&#178;+0.13x5+0.22x6-72.78 &#963;= 4.5 [7] z = - 2. l0x&#185; + 0. 05x&#178;+ 0. 11 x5 - 0. 08x6+ 113.4 &#963;= 10. 7.. · [7]' where x5 is the time when the number of mosquitoes (C. T. collected by light trap reached the maximum and X6 is the time when hazardous mosq uitoes were dected. In the case of median date, 5 prefectures out of 6 prefectures by [5], 2 out of 6 by [6] and 2 out of 5 by [7], and in the case of mode date, 5 out of 6 by [5]', 4 out of 5 by [6]' and 4 out of 5 by [7]' could be accurately estimated in 1969.</p

The Study on the Evaluation of the Visual Work Using the Logistic Curve

Display equipment has been used as communication media in the factory, office, and home. In order to communicate effectively, it is necessary to clarify the characteristics of eye movement in the case of looking at the display. The development of Eye Camera enables us to measure eye movement during work, so that we can collect the many data of eye movement during work. In this study, we proposed a method to evaluate the visual work using the distribution of visual points in X and Y axis. The cumulative distribution is approximated by the logistic curve which shows the symmetry and kurtosis by the parameter. The proposed method was applied to the three typical display models, that is, the digital meter model, reading model, and game model. In the digital meter model, the visual points were distributed symmetrically along the meters, and the symmetry and kurtosis of the distribution varied by the arranged direction of the meter. In the reading model, the visual points were distributed nearly symmetrically and uniformly in each axis and they were moved around the character and line from the period of spectrum analysis. In the game model, the visual points moved according to the target and were distributed symmetrically in the Y axis. And whether the target moved vertically or horizontally, the kurtosis of the distribution became equal in each axis

On a Relation between the Flicker value and the Working Condition

The appropriate disposition of the worker improves the ability of the worker and the efficiency of the labor and further decreases the rate of inferior goods and the rate of accidents. In previous paper, the variation of the flicker value, the trend of the miss frequency and the relation between them under the condition which has one surveillance point and one back-ground condition are analyzed. In this paper, the surveillance point is increased to two points and the back ground condition also two in order to examine which condition influences strongly to the flicker value in the working time. It was found that the variation of the flicker value is strongly connected with the qualification, the number of the surveillance and its miss-frequency

A Logical Problem Decomposing Method for Decision Makers

Decision Support Systems (DSS) have been taken as hopeful support tools for decision making for more than 20 years. There are a lot of literatures on DSS, but most of them are not so practical as the designers expected. This paper points out the crux of this situation and argues that the research on DSS should pay some more attention to the decision making activities before the model using stage. A method named "Problem Situation Decomposing Graph (PSDG)" is presented in this paper for helping the decision maker(DM) elicit the decision making problems. A PSDG is an acycle AND/OR logical directed graph, and which includes all the factors affecting the problem situation based on the DM's knowledge. The logical nodes and parameter determining methods in PSDG can reflect the DM's decision making style. This paper introduces some basic concepts of PSDG, discusses some of its characteristics, and proposes a logical adjacency matrix for PSDG representation and analysis

On a Study of the Empirical Formula to Explain the Work Amount

This paper deals with the empirical formula to explain the work amount curve of a worker during a work. The empirical formula yt = at(b) + c was used to explain this phenomenon until now. This formula has been used mainly to approximate to the monotonous trend of the work amount curve. But it was made clear that if the work amount curve showed the polynomial trend, it could not be done so. Then the authors attempt to establish the empirical formula yt = a/{exp(Σb(i)t(i))-l} + c, which was the general form of the logistic curve in order to explain not only the monotonous trend but also the polynomial trend of the work amount curve. And it was made clear from the results of the approximation that this formula was the one of the most usuful formula in order to explain the work amount curve

Selection and application of factors for forecasting the epidemic time and severity of Japanese encephalitis prevalence

For predicting median date or incidence rate in the prevalence of japanese encephalitis, the authors considered the 34 factors; namely, the climate, latitude, longitude, and date showing immunological positivity of hemoagglutination inhibiting reaction on 50% the number of swine, etc. To make the mean square residual the smallest which yields, in the case of calculating with the multiple regression equation, the most important and meritorious factors were selected from the factors mentioned above by the voluntary selection rule devised by us. Multiple regression equations were formulated for them. To predict the median date in the prevalence of japanese encephalitis in whole japan, we found that the three factors, i. e. the amount of rainfall in April, the average temperature in March and HI positive rate of swine till the end of july, were essential. And for the foreseeing of incidence rate in Okayama Prefecture, factors concerning mosquitoes were added; this resulted in the useful two factors, namely, common logarithm of the total number of Culex tritaeniorhynchus till july 20th and the rainfall in June.</p

A Computer Program of Assembly Line Balancing Considering the Performance Rate of Each Work Station

Assembly line balancing is to assign work elements to serial work stations so as to make the work content at each station as close as possible to one limiting cycle time or pitch time, i.e., an upper time limit over every station. Until now, it is usually assumed that the performance rates of work stations are constant. But in practice the performance abilities of workers, machines or robots are varied by their own working conditions. Then the actual station times are different from standard ones, and consequently the line balance may diminish in many cases. Therefore in this paper, we propose an improved balancing method, in which work elements can be assigned to the work station having the upper time limit changed by its performance rate or ability. Further we develop the computer program of the proposed method and provide an illustrative problem and computational results. In an application of our method to the practical problems, it is shown that the actual efficiency of the production line becomes near that planned

An Expert System for the Scheduling of a Flexible Assembly Line for Multi Item Products

An expert system, in which preconditions and rules are expressed in logical formulas, is developed to support the scheduling of an automated job shop type multi-item assembly line. This system has the foIIowing characteristics to apply any case of schedulings: (1)Forward scheduling orbackward scheduling can be made. (2)The criterion on the input order of products, the dispatching process at each assembly station, and the selection of products from a buffer can be selected from several priority criteria. (3)Layout, number and velocity of vehicles, and the capacity of each buffer can be changed

Computer Program of Forward Selection and Backward Elimination Procedure in Linear Discriminant Analysis and Test forDifferences Between Mean Values of Two Populations

In multivariate analysis, the linear discriminant analysis and the test for differences between mean values of two populations are of wide application. It is not essential to increase the variables only in order to increase the degree of accuracy of discrimination or test without evaluating the effect of variables. Therefore the computer program of selection procedures of variables in these two methods is mentioned in this paper

On the Trial Production of the Equipment Measuring ManySubjects' Critical Flicker Fusion Frequency at the Same Time

The equipment measuring the critical flicker fusion frequency (CFF) is made in order to measure many subjects' CFF at the same time. This equipment is defined the multi-flicker. The equipment measuring CFF, used until now is defined the mono-flicker. It is analysed what factors influence CFF strongly. Then it is made clear that CFF value measured by the multi-f1icker can be used to show the brain weariness as well as that of the mono-flicker, and the vigual angle and the intensity of illumination in the room influence CFF value strongly