• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.422-425
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• 1991

This paper presents the effect of the voltage proximity index for the voltage collpase in power systems. The reactive generation limits are considered for the determination of the voltage proximity index. This paper also shows how the VAR investment ranking order works by the sensitivity index(proximity index). Simulation has carried out with the IEEE 14 bus system and has shown the voltage proximity index working well.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.222-230
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• 2017

Background: Varicella is the most common infectious disease reported despite the high vaccination rate. Interventions that target humans are particularly effective for varicella because humans are its only natural host. On the other hand, the existing national varicella surveillance systems lack the information to identify an outbreak. Therefore, a new index to assess varicella outbreaks was developed. Methods: The residential addresses of 2,718 varicella cases reported in Daegu in 2016 were converted to geographic coordinates and the distances between new varicella case and previous cases within 21 days were calculated from the date analyzed. Two cases were considered to be adjacent if the distance between them was less than 1 km. Finally, a proximity index was introduced by dividing the number of adjacent cases by the number of new cases on the date analyzed. Results: First, time-series charts and scatter plots were used to verify that the proximity index reflected the spatial closeness of the different varicella cases. The proximity index is helpful in identifying outbreaks from a list of single varicella cases. In addition, in this study, a new epidemic characteristic of varicella based on the proximity index was shown. Conclusion: The proximity index introduced in this study can be used to determine the likelihood of an outbreak from a single case of varicella, and it can be embedded in a web-based national varicella surveillance system that is currently in operation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.10
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• pp.1290-1294
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• 1995

In this paper, a new voltage collapse proximity index (VCPI) based on system apparent power loss sensitivity is proposed. The newly proposed index .lambda.$^{Sloss}$ reaches -.inf. at system voltage collapse point and can be represented by .root..lambda.$^{Ploss}$$^{2}$+.lambda.$^{Qloss}$$^{2}$ where .lambda.$^{Ploss}$ and .lambda.$^{Qloss}$ are the VCPI based on the system active and reactive power loss sensitivity respectively. These indices can be used for the system VAR investment. .DELTA.Q [VAR] is invested, step by step, by the priority of the VCPI index given for each bus. The indices use information from normal power flow equations and their Jacobians. Computation time for deriving .lambda.$^{Sloss}$ is almost same as that for power flow calculation. Two case studies prove the effectiveness of the .lambda.$^{Sloss}$ index and the VAR investment algorithm proposed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.4
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• pp.363-372
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• 1997

We have developed the UHF CW/FM proximity sensor system. The UHF CW/FM Proximity Sensor is the system which recognizes the distance from the antenna to the target using the UHF band signal. To adjust sensing distance, we must change modulation frequency parameter or modulation index parameter. When we select the modulation frequency paramter for adjusting sensing distance, new modulation frequency generator and new band pass filter will be required. It is so inefficient that we choose modulation index parameters for adjusting sensing distance. In this paper, theoretical principles of the UHF CW/FM Proximity Sensor are analyzed and doppler signals for the distance from the antenna to the target are measured as the modulation index($\beta$) being changed. Three systems of which moduation indices are 38, 50, and 61 are made. We concluded that the sensing distance will decrease as the modulation index($\beta$) increases. It is in accord with the theory of this UHF CW/FM Proximity Sensor System.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.218-221
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• 1992

Recent years voltage collapse phenomenon have a great attention to power system engineers. As the system size increases the voltage problem shows a very complicated and the reactive power contol problem becomes more difficult. This paper gives an efficient methods for calculating voltage collapse proximity index based on the reactive power loss sensitivity and real power loss sensitivity. The system voltages are tightly associated with the system reactive power, so the proposed voltage collapse proximity index is very usefull for the system voltage control problems. Numerical examples showed a good and reliable results.

• Journal of the Korean Geographical Society
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• v.36 no.4
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• pp.434-443
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• 2001

Differing from the existing method to optimize the statistical proximity, the new optimization method was developed to maximize the spatial proximity among the unit areas of choropleth map. 25 choropleth maps were made using 5 classification methods(maximum BEI, maximum TEI, equal interval, natural break, n-tile) for 5 classes(3∼7) and were analyzed to elucidate the effectiveness of classification methods on the basis of 3 evaluation indeces (TEI, BEI, $C_{F}$). The results from the maximum TEI and maximum BEI were evaluated as relatively stable and effective compared to those from other classification methods. But they showed the opposite trends owing to the trade-off relationships. Meanwhile, the resets from the natural break method got higher marks, which was also identified through the analysis using a new $alpha$-index.x.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.604-613
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• 2018

In this study, we analyzed the variations in the received signal strength index (RSSI) measured from Bluetooth beacons based on the strength and propagation direction of Bluetooth low energy (BLE) signal. Using a smartphone, we performed field experiments to investigate RSSI variations in the BLE signal transmitted by non-directional and directional beacons in an amethyst mine. In case of non-directional beacons, as the distance between the Bluetooth beacon and smartphone decreased, the RSSI increases, whereas as the BLE signal strength increased, the RSSI average gradually increased. The mean value of RSSI measured from the directional beacons was changed without relation to the facing angle between the Bluetooth beacon and smartphone. The results of this study can be used as basic data for developing a Bluetooth beacon-based proximity warning system for underground mines.

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.77-88
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• 1999

A new measure of the process capability index(PCI) $\textit{C}_{cpk}$ is proposed that takes into account the proximity to the target value as well as process mean and process variation when we assessing process performance. using the semivariance estimators proposed by Choobineh and Branting (1986) and Josephy and Aczel (1993) the estimator($\textit{C}_{cpk}$) of new index has been solved and the properties of these estimators have been examined through simulations. Also we compare the performance between $\textit{C}_{cpk}$ and $\textit{C}_{jpk}$ which is developed by Johnson kotz and Pearn(1992).

• Journal of Preventive Medicine and Public Health
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• v.46 no.5
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• pp.226-236
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• 2013

Objectives: The aim of this study was to examine the levels of serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and evaluate their association with age, body mass index, smoking, military record-based variables, and estimated exposure to Agent Orange in Korean Vietnam veterans. Methods: Serum levels of TCDD were analyzed in 102 Vietnam veterans. Information on age, body mass index, and smoking status were obtained from a self-reported questionnaire. The perceived exposure was assessed by a 6-item questionnaire. Two proximitybased exposures were constructed by division/brigade level and battalion/company level unit information using the Stellman exposure opportunity index model. Results: The mean and median of serum TCDD levels was 1.2 parts per trillion (ppt) and 0.9 ppt, respectively. Only 2 Vietnam veterans had elevated levels of TCDD (>10 ppt). The levels of TCDD did not tend to increase with the likelihood of exposure to Agent Orange, as estimated from either proximity-based exposure or perceived self-reported exposure. The serum TCDD levels were not significantly different according to military unit, year of first deployment, duration of deployment, military rank, age, body mass index, and smoking status. Conclusions: The average serum TCDD levels in the Korean Vietnam veterans were lower than those reported for other occupationally or environmentally exposed groups and US Vietnam veterans, and their use as an objective marker of Agent Orange exposure may have some limitations. The unit of deployment, duration of deployment, year of first deployment, military rank, perceived self-reported exposure, and proximity-based exposure to Agent Orange were not associated with TCDD levels in Korean Vietnam veterans. Age, body mass index and smoking also were not associated with TCDD levels.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.119-122
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• 2005

In this paper, we investigated the recognition range according to modulation index for the ISO(International Standards Organization) 14443 13.56MHz contactless Type B RFID(Radio Frequency IDentification) system. We measured recognition range with changing modulation index step by step from 5% to 24% where we used 4 samples of Type B transponder with different resonance frequencies between 13.838MHz and 17.200MHz. While gradually increasing a distance in vertical direction from the center of the reader antenna, we measured the distance where the transponder's PUPI(Pseudo Unique PICC(Proximity IC Card) Identifier) is recognized continuously during 10 seconds and the distance where the transponder's PUPI is recognized at least two times during 5 seconds. From the measurement results, we found that the best recognition ranges were achieved when the reader had modulation index between 11% and 14%.