• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.191-196
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• 2014

The solar water heating system is one of the seven green campus items installed at the Gangneung campus of Gangneung-Wonju National University. The solar water heating system has two types of solar collectors, four storage tanks and monitoring equipment. Fixed and azimuth-tracking solar collectors were installed to collect heat from the sun. The amount of heat collected by the two different types of solar collectors was calculated from the temperature of the monitored storage tanks. Our results showed that the amount of solar heat collected by the azimuth-tracking solar collector was 19% greater on a sunny day and 23% greater on a rainy day than that collected by the fixed solar collector; therefore, the azimuth-tracking solar collectors are, on an average, 21% more efficient than the fixed solar collectors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.414-418
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• 2009

In this paper, a solar power tracking method using the solar cells is proposed, which has 3 solar cell located at an interval of $60^{\circ}$ in azimuth so that the sunlight may almost be perpendicular to the solar cells without excessive mechanical operation. Compared with the solar cell voltages in each azimuth, there is the highest voltage in time interval. As a results, this solar cell system achieve higher relative efficiency of $1.6{\sim}11.5%$ than fixed solar cell system. Therefore, it is verifying that this solar cell tracking system obtain more relative efficiency than fixed solar cell system for aid to navigation.

• 전자공학회논문지 IE
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• v.48 no.1
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• pp.25-29
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• 2011

Ryu et al. proposed a multiple target angle-tracking algorithm with efficient equation for angular innovation, and Ryu's algorithm has good feature that it has no data association problem. Ryu's algorithm is only applicable to linear sensor array, because its efficient equation for angular innovation is derived in case of using a linear sensor array. In a many fields studying multiple target angle-tracking, the various shapes of sensor array are used. In sonar, a cylindrical sensor array is as much used as a linear sensor array, a example is hull mounted sonar. In this paper, Ryu's algorithm is modified to be applicable to cylindrical sensor array, and the tracking performance of a modified algorithm is verified by various computer simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4733-4739
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• 2012

While traditional two-axis tracking systems with double sensors had been using two sensors to control azimuth and elevation angle of the sun so that a solar cell module would make a normal line with the sun, this paper proposed a new two-axis system that can achieve the same performance with only one sensor in it. It is Two-axis tracking system that control azimuth and elevation to control to be reduced for solar cell module as proposed tracking system uses 1 sensors and the sun always forms normal. Two-axis tracking system of one sensor method that propose in paper that could reduce electric power consumption and sees than fixed type preventing action and the most efficient driving and needless drive could confirm that generation efficiency of about 23 [%] increases. To heighten efficiency of solar cell doing to receive more sunlights chasing the sun, done tracking device have proceeded a lot of studies in large size way. Therefore, is expected that will do big part in the sun tracking supply through utility study about persistent generation efficiency constructing monitoring system of the sun tracking of this paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.7
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• pp.492-497
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• 2011

The objective of this research is to study the variation of optimum slope angles of collectors for seven regions in Korea, which are Seoul, Gangneung, Daejeon, Daegu, Gwangju, Busan and Jeju. The results for 2000~2007 are analyzed to sec if adjustment of slope angles is necessary each year to receive maximum solar radiation. For an azimuth fixed solar collector, solar radiation of yearly optimized slope angle during May~Sept.(summer), Nov.~Mar.(winter) and the whole year are greater than the fixed slope angle by 0.03%, 0.02%, and 0.04%, respectively. For an azimuth tracking solar collector, solar radiation of yearly optimized slope angle during May~Sept.(slimmer), Nov.-Mar.(winter) and the whole year are greater than the fixed slope angle by 0.03%, 0.07%, and 0.04% respectively. It is unnecessary to adjust slope angles each year for both azimuth fixed and tracking collectors, since the gains are insignificant. Solar radiation of the azimuth tracking solar collector during May~Sept., Nov.~Mar. and the whole year are greater by 14.7%, 16.0%, and 19.2% than the azimuth fixed solar collector.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.260-265
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• 2003

The energy of PV system is different as the elevation and aximuth of the sun. This paper deals with the economical position tracking system development for the stand alone PV system. We have made more economical solar position tracking system which is used a tracking program than other similar systems. It is applied to the solar lighting lamp. We have made a comparative study of the energy amount between the fixed type and the tracking type during some period. The improved efficiency of the system is about 86 %.

• The Journal of the Convergence on Culture Technology
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• v.4 no.3
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• pp.299-303
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• 2018

Generally, when predicting the accuracy of the anti-air artillery system, the error is classified as fixed bias, variable bias, and random error. Then the standard deviation on the target is expressed as the square root of the squared sum of each error value which comes from the random error and variable bias and in the case of fixed bias, the mean value is shifted as the sum of errors from the fixed bias. At this time, the variables indicating the displacement of the direction of azimuth and elevation direction with regard to the change of the unit value of each error are weighted. These errors are then used to predict the system's delivery accuracy through a normally distributed integral. This paper presents a method of predicting system accuracy by considering the correlation of errors. This approach shows that it helps to predict the delivery accuracy of the system, precisely.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.75-80
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• 2019

In the recent aerospace and defence industries, it is required to develop small and low cost embedded systems. Based on a high speed digital signal processor (DSP), this paper first presents the development of an embedded system. To reduce the computation time of the high precision algorithm such as flight control, we also propose two algorithms for matrix multiplication. Validation results show that, compared to the performance using the $2{\times}2$ unit method, the performance of the proposed method 1 is improved, when the size of matrices is small. The proposed method 2 generally outperforms the $2{\times}2$ unit method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1A
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• pp.105-113
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• 2008

Solar radiation induces non-uniform temperature distribution in the bridge structure depending on the shape of the structure and shadows cast on it. Especially in the case of curved steel box girder bridges, non-uniform temperature distribution caused by solar radiation may lead to unusual load effects enough to damage the support or even topple the whole curved bridge structure if not designed properly. At present, it is very difficult to design bridges in relation to solar radiation because it is not known exactly how varying temperature distribution affects bridges; at least not specific enough for adoption in design. Standard regulations related to this matter are likewise not complete. In this study, the thermal behavior of curved steel box girder bridges is analyzed while taking the solar radiation effect into consideration. For the analysis, a method of predicting the 3-dimensional temperature distribution of curved bridges was developed. It uses a theoretical solar radiation energy equation together with a commercial FEM program. The behavior of the curved steel box girder bridges was examined using the developed method, while taking into consideration the diverse range of bridge azimuth angles and radii. This study also provides reference data for the thermal design of curved steel box girder bridges under solar radiation, which can be used to develop design guidelines.