• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.5
• /
• pp.636-642
• /
• 1999

The synthesis of the 3D images is the most important part of the virtual reality. The ray tracing is the best method for reality in the 3D graphics. But the ray tracing requires long computation time for the synthesis of the 3D images. So, we implement the ray tracing with software and hardware. Specially we design the hit-test unit with FPGA tool for the ray tracing. Hit-test unit is a very important part of ray tracing to improve the speed. In this paper, we proposed a new hit-test algorithm and apply the parallel architecture for hit-test unit to improve the speed. We optimized the arithmetic unit because the critical path of hit-test unit is in the multiplication part. We used the booth algorithm and the baugh-wooley algorithm to reduce the partial product and adapted the CSA and CLA to improve the efficiency of the partial product addition. Our new Ray tracing processor can produce the image about 512ms/F and can be adapted to real-time application with only 10 parallel processors.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.2
• /
• pp.288-292
• /
• 2013

This paper presents the result of life-cycle cost (LCC) estimation for domestic products propulsion control system (motor block unit) of KTX-1 considering periodic maintenance. Life cycle costing is one of the most effective approaches for the cost analysis of long-life systems such as the KTX-1. Life cycle costing includes the cost of concept design, development, manufacture, operation, maintenance and disposal. To estimate LCC for domestic products motor block unit, it was analyzed physical breakdown structure (PBS) on motor unit in view of maintenance cost and unit cost etc. As a results, life cycle cost on motor block unit increased moderately expect for periodical time when major parts are replaced at the same time. hereafter this results will be reflected in the domestic products being developed.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.11a
• /
• pp.29-30
• /
• 2022

The unit-water content has a very significant effect on the durability of the construction structure and the quality of concrete. Although there are various methods for measuring the unit-water content, there are problems of time required for measurement, precision, and reproducibility. Recently, there is an FDR sensor capable of measuring moisture content in real time through an apparent dielectric constant change of electromagnetic waves. In addition, various artificial intelligence techniques that can non-linearly supplement the accuracy of FDR sensors are being studied. In this study, the accuracy of unit-water content measurement was compared and evaluated using machine learning and deep learning techniques after normalizing the data secured in concrete using frequency domain reflectometry (FDR) sensors used to measure soil moisture at home and abroad. The result of comparing the accuracy of machine learning and deep learning is judged to be excellent in the accuracy of deep learning, which can well express the nonlinear relationship between FDR sensor data and concrete unit-water content.

• Journal of Korea Water Resources Association
• /
• v.56 no.10
• /
• pp.655-665
• /
• 2023

In this study, unit hydrographs are calculated when precipitations of 10 scales instantaneously occurs in a virtual watershed with a constant slope and roughness. Then, the relationship between the peak flow rate and the peak occurrence time of the unit hydrograph was calculated for the precipitation scale, respectively. At this time, the virtual watershed simplified with a rhombic shape, a constant slope, and a flow condition with a certain roughness was applied instead of a natural watershed in order to understand the effect the precipitation scale has on the peak value of the unit hydrograph. And it was assumed that the precipitation in the basin was effective rainfall and the runoff was direct runoff, and the runoff flowed in a straight, uniform flow from the drop point to the outlet. The relationship between the peak flow and the peak occurrence time of the unit hydrograph was calculated in the case of 10 types of precipitation scales of 10 mm, 40 mm, 90 mm, 160 mm, 250 mm, 360 mm, 640 mm, 1,000 mm, 1,210 mm, and 1,690 mm of effective precipitation. A noteworthy achievement of this study is that, even without the storage effect of the watershed, as the scale of precipitation increases, the depth of runoff increases, so the flow rate in the watershed increases and the distance per unit time increases, so the peak flow rate increases and the peak occurrence time increases. This is a nonlinear characteristic of watershed runoff.

• Proceedings of the Korean Reliability Society Conference
• /
• 2000.11a
• /
• pp.387-395
• /
• 2000

Circular consecutive-k-out-of-n:F system when the failure of component is dependent is studied. We assume that the failure of a component in the system increase the failure rate of the survivor which is working just before the failed component. In this case, a mean time to failure (MTTF), a average failure number of the system, and the expected cost per unit time are obtained. Then the minimum number of consecutive failed components to cause system failure to minimize the expected cost per unit time is determined as searching paths to system failure. And various numerical examples are studied.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.10 no.16
• /
• pp.27-38
• /
• 1987

This paper develops a standard time table using STD(Standard Tine Data) Technique in multi-product and one-unit production systems. STD leads to greater consistency between similar jobs. The constant-time and special elements will always be the same even though they pertain to different part numbers. Actually, the standards will very based on the size of the variable elements that are in control of the time. A real-field example is presented.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.4 s.42
• /
• pp.35-45
• /
• 2006

RIn this paper. we describe real-time parallel processing simulator developed for the use of performance analysis of rolling missiles. The real-time parallel processing simulator developed here consists of seeker emulator generating infrared image signal on aircraft, real-time computer, host computer, system unit, and actual equipments such as auto-pilot processor and seeker processor. Software is developed according to the design requirements of mathematic model, 6 degree-of-freedom module, aerodynamic module which are resided in real-time computer. and graphic user interface program resided in host computer. The real-time computer consists of six TI C-40 processors connected in parallel. The seeker emulator is designed by using analog circuits coupled with mechanical equipments. The system unit provides interface function to match impedance between the components and processes very small electrical signals. Also real launch unit of missiles is interfaced to simulator through system unit. In order to use the real-time parallel processing simulator developed here as a performance analysis equipment for rolling missiles, we perform verification test through experimental results in the field.

• Journal of Korean Academy of Nursing
• /
• v.25 no.3
• /
• pp.441-456
• /
• 1995

This study was done to determine direct and in-direct nursing time in nursing units in hospital to ap-plied computer system and expect that those results contribute to measure efficiency of nursing practice and planning of nursing manpower. The design for study was a descriptive study. The study results are as follows. 1. Patients admitted to the Internal Medicine and General Surgery units were grouped into four. Group Ⅰ, 32.9% of the total patients, consisted patients whose condition was considered minor Group Ⅱ, 26.1%, was of those whose condition was considered moderate, Group Ⅲ, 41. 8%, moderate severe and Group Ⅳ, 29.2% the most severe. 2. Nursing intervention times by care type were as follows four minutes spent for suction eight minutes, for simple position change, ten minutes, for sheet change, seven minutes for a hot or cool compress, six minutes for dressing change, four minutes for Ⅰ.M. injection, six minutes for patient health education and five minutes for body temperature check. 3. Direct care time by patient group revealed the following : Group Ⅰ rquired 191.4 minutes, Group Ⅱ required 331.1 minutes, Group Ⅲ rquired 499.4 minutes, and Group Ⅳ rquired 1328.0 minutes. 4. The ratio of time for adequate nursing care and direct care time in the Internal Medicine and Goneral Surgery units was 67.4%-83.4% and 94.7%-99.3% in the Intensie Care Unit. 5. Average daily direct care time per patient was 5.5 hours in the Internal Medicine unit and 11.5 hours in the Intensive Care Unit. 6. Time spent in indirect care was 48.3 minutes for computer recording,34.8 minutes for giving and receiving patient information for shift duty, 28.0 minutes for eating and resting time, 26.6 minutes for transfering and identifying patients, 25.6 minutes for identifying Doctor's order, 23.9 minutes for recording vital signs. 7. Time spent in indirect care was 282.2 minutes by head nurses (charge nurses), 258.7 minutes by nurses and 261.6 minutes by nurse aids. 8. The average nurse's workload was 9.3 hours and daily indirect nursing time required 46.3%-50. 5% of above mentioned workload time. .9. The average daily indirect care time per patient was expected to be 57.7 minutes in the Internal Medicine unit and 3.3 hours in the Intensive Care Unit.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.15
• /
• pp.6455-6459
• /
• 2014

Background: Nasopharyngeal carcinoma (NPC) is the fourth most common cancer in Malaysia. The objective of this study was to determine the five-year survival rate and median survival time of NPC patients in Hospital Universiti Sains Malaysia (USM). Methods: One hundred and thirty four NPC cases confirmed by histopathology in Hospital USM between $1^{st}$ January 1998 and $31^{st}$ December 2007 that fulfilled the inclusion and exclusion criteria were retrospectively reviewed. Survival time of NPC patients were estimated by Kaplan-Meier survival analysis. Log-rank tests were performed to compare survival of cases among presenting symptoms, WHO type, TNM classification and treatment modalities. Results: The overall five-year survival rate of NPC patients was 38.0% (95% confidence interval (CI): 29.1, 46.9). The overall median survival time of NPC patients was 31.30 months (95%CI: 23.76, 38.84). The significant factors that altered the survival rate and time were age (p=0.041), cranial nerve involvement (p=0.012), stage (p=0.002), metastases (p=0.008) and treatment (p<0.001). Conclusion: The median survival of NPC patients is significantly longer for age ${\leq}50$ years, no cranial nerve involvement, and early stage and is dependent on treatment modalities.

• Communications for Statistical Applications and Methods
• /
• v.19 no.1
• /
• pp.177-182
• /
• 2012

A structural break in the level as well as in the innovation variance has often been exhibited in economic time series. In this paper we propose robust unit root tests based on a sign-type test statistic when a time series has a shift in its level and the corresponding volatility. The proposed tests are robust to a wide class of partially stationary processes with heavy-tailed errors, and have an exact binomial null distribution. Our tests are not affected by the size or location of the break. We set the structural break under the null and the alternative hypotheses to relieve a possible vagueness in interpreting test results in empirical work. The null hypothesis implies a unit root process with level shifts and the alternative connotes a stationary process with level shifts. The Monte Carlo simulation shows that our tests have stable size than the OLSE based tests.