• Annual Conference of KIPS
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• 2013.11a
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• pp.1404-1407
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• 2013

Mobile phone GPS positioning system is a function we often use, which can make user locate his own position all time. But due to lots of inconvenience brought to us by some error existing in mobile phone positioning system, how to accurately position becomes a hot research topic at home and abroad. This paper puts forward a way of precise calculating position. Firstly, take object's image with mobile phone camera; then, process the image to extract and identify object inside; finally, calculate the distance between the object and user with the object's information stored in the database.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.86-91
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• 2022

Cache bypassing is a scheme to prevent unnecessary cache blocks from occupying the capacity of the cache for avoiding cache contamination. This method is introduced to alleviate the problems of non-volatile memories (NVMs)-based memory system. However, the prior works have been studied without considering wear-out attack. Malicious writing to a small area in NVMs leads to the failure of the system due to the limited write endurance of NVMs. This paper proposes a novel scheme to prolong the lifetime with higher resistance for the wear-out attack. First, the memory reference pattern is found by modified reuse distance calculation for each cache block. If a cache block is determined as the target of the attack, it is forwarded to higher level cache or main memory without updating the NVM-based cache. The experimental results show that the write endurance is improved by 14% on average and 36% on maximum.

• International Journal of Korean Welding Society
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• v.1 no.1
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• pp.39-43
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• 2001

In this paper, the neutron diffraction is applied to the residual stress measurement on the 20mm-thick welded stainless steel plate ($100^{\circ}$$\times$100$mm^2$). The High Resolution Powder Diffractormeter of the Korea Atomic Research Institute The power of nuclear reactor was 24 MWt and the measured reflection in the 220 plane (2$\theta$ is $95^{\circ}$and wavelength is 1.8340 ${\AA}$ . The Poisson ratio of 0.265 and elastic constant of 211 GPa are applied to the calculation of stresses and strains. Three directional components such as normal, transverse, and longitudinal stresses are measured and the results show that the most of longitudinal stress is tensile and decreases, changing to compressive depending on the distance away from the welded spot. However, transverse component is changing from tensile to compressive along the depth of the welded point.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.49-58
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• 1997

In process planning for pocket machining, the selection of tool size, tool path, overlap distance, and the calculation of machining time are very important factors to obtain the optimal process planning result. Among those factors, the tool size is the most important one because the others depend on tool size. And also, it is not easy to determine the optimal tool size even though the shape of pocket is simple. Therefore, the optimal selection of tool size is the most essential task in process planning for machining a pocket. This paper presents a method for selecting optimal toos in pocket machining. The branch and bound method is applied to select the optimal tools which minimize the machining time by using the range of feasible tools and the breadth-first search.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.479-484
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• 2007

For calculation of wave field for design of coastal and port structures, generally the wind fields from inland observation record or the predicted waves from deep water wave transformation model are being used. However, for the first case, as we should revise the wave data adopting correcting parameters depending on the distance from the coast and location, it is difficult to extract water waves from wind field. Furthermore, for the second case, because of the calculation which executed under very large grid sizes in the wide domain, the simulation(wave transformation) implied uncertainty in the near shore area and shallow region. So it's difficult to obtain exact data from the simulation. Thus, in this study the calculation of wave field on shallow water is accomplished using the observed data of typhoon 'Maemi' in the Korea Eastern South sea. Moreover, for the accuracy of the calculated wave field, we compared and studied the observed data of wave height and direction on the vicinity of the Ulsan waters. It is proved that the results of this study is more accurate than the existing method with showing ${\pm}1.3%$ difference between observed and calculated wave height distribution in Ulsan waters

• Progress in Medical Physics
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• v.13 no.1
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• pp.21-26
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• 2002

A practical calculation algorithm which calculates the relative output factor(ROF) for irregular shaped electron field has been developed and evaluated the accuracy of the algorithm. The algorithm adapted two-source model, which assumes that the electron dose can be express as sum of the primary source component and the scattered component from the shielding block. Original two-source model has been modified in order to make the algorithm simpler and to reduce the number of parameters needed in the calculation, while the calculation error remains within clinical tolerance range. The primary source is assumed to have Gaussian distribution, while the scattered component follows the inverse square law. Depth and angular dependency of the primary and the scattered are ignored ROF can be calculated with three parameters such as, the effective source distance, the variance of primary source, and the scattering power of the block. The coefficients are obtained from the square shaped-block measurements and the algorithm is confirmed from the rectangular or irregular shaped-fields used in the clinic. The results showed less than 1.0 ％ difference between the calculation and measurements for most cases. None of cases which have bigger than 2.1 ％ have been found. By improving the algorithm for the aperture region which shows the largest error, the algorithm could be practically used in the clinic, since one can acquire the 1011 parameter's with minimum measurements(5∼6 measurements per cones) and generates accurate results within the clinically acceptable range.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.4
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• pp.310-317
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• 2017

Recently, many nations are operating and developing Global Navigation Satellite System (GNSS). Also, Satellite Based Augmentation System (SBAS), which uses the geostationary orbit, is operated presently in order to improve the performance of GNSS. The most widely-used SBAS is Wide Area Augmentation System (WAAS) of GPS developed by the United States. SBAS uses various algorithms to offer guaranteed accuracy, availability, continuity and integrity to its users. There is algorithm for guarantees the integrity of the satellite. This algorithm calculates the satellite errors, generates the correction and provides it to the users. The satellite orbit errors are calculated in three-dimensional space in this step. The reference placement is crucial for this three-dimensional calculation of satellite orbit errors. The wider the reference placement becomes, the wider LOS vectors spread, so the more the accuracy improves. For the next step, the regional features of the US and Korea need to be analyzed. Korea has a very narrow geographic features compared to the US. Hence, there may be a problem if the three-dimensional space method of satellite orbit error calculation is used without any modification. This paper suggests a method which uses scalar values to calculate satellite orbit errors instead of using three-dimensional space. Also, this paper proposes the feasibility for this method for a narrow area. The suggested method uses the scalar value, which is a projection of orbit errors on the LOS vector between a reference and a satellite. This method confirms the change in errors according to the baseline distance between Korea and America. The difference in the error change is compared to present the feasibility of the proposed method.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.243-252
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• 1994

The use of high dose rate remote afterloading system for the treatment of intraluminal lesions necessitates the need for a more accurate of dose distributions around the high intensity brachytherapy sources, doses are often prescribed to a distance of few centimeters from the linear source, and in this range the dose distribution is very difficult to assess. Accurated and optimized dose calculation with stable numerical algorithms by PC level computer was required to treatment intraluminal lesions by high dose rate brachytherapy system. The exposure rate from sources was calculated with Sievert integral and dose rate in tissue was calculated with Meisberger equation, An algorithm for generating a treatment plan with optimized dose distribution was developed for high dose rate intraluminal radiotherapy. The treatment volume becomes the locus of the constrained target surface points that is the specified radial distance from the source dwelling positions. The treatment target volume may be alternately outlined on an x-ray film of the implant dummy sources. The routine used a linear programming formulism to compute which dwell time at each position to irradiate the constrained dose rate at the target surface points while minimizing the total volume integrated dose to the patient. The exposure rate and the dose distribution to be confirmed the result of calculation with algorithm were measured with film dosimetry, TLD and small size ion chambers.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.31-42
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• 2019

Among the driving information recorded in the event data recorder (EDR), the speed information of the vehicle before the traffic accident is a very important factor that determines the punishment of the driver of the accident vehicle, the identification of the offender and the victim, and the possibility of avoiding the accident. Also, by analyzing the EDR data, the deceleration of the accident vehicle can be analyzed. In this study, the results of the braking test of the previous study and the analysis of the EDR data of the traffic accident vehicle were compared to suggest an appropriate deceleration value applicable to the calculation of the stopping distance. As a result of the braking test of the vehicle equipped with ABS of the previous study, the average deceleration of the vehicle was 0.79g ~ 0.94g. In addition, the deceleration value was calculated from 0.92g to 0.94g in the recent automobile safety evaluation braking test conducted by the Korea Automobile Testing & Research Institute. In addition, the deceleration value of 0.55g ~ 0.71g was calculated through the analysis of EDR data performed in this study, and the value was smaller than the deceleration value measured in the braking experiment of the previous study.

• Progress in Medical Physics
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• v.12 no.2
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• pp.147-153
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• 2001

We have discussed that the total body irradiation(TBI) dose distribution of 6 and 10 MV photon beams, also differences between calculation dose use of compensator sheet and measurements in humanoid phantom. Total body irradiation and hemi-body irradiation(HBI) can be effectively performed when uniformity of dose distribution is estabilished. The method of TBI and HBI dosimatry requires special considerations related to technique, long distance and very large field, machine parameter, patient positioning. TBI and HBI with megavoltage photon beams requires basic dosimatric data which have to be measured directly or derived from the standard beam data. The semiconductor detector and ion chamber were positioned at a dmax depth, mid depth, and its specific ratio was determined using a scanning data by RFA-7 3-dimensional water phantom and solid phantom. The effective source axis distance 380 cm, the field size from 120 cm to 152 cm, isodose distributions were analyzed as a function of the thickness in phantom. Also, have discussed that the measurement of basic data for clinical photon beams for dosage calculations, data calculation sheet and the use of tissue compensation to improve dose uniformity. We have improved a dose uniformity in the TBI and HBI method.