• Fire Science and Engineering
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• v.18 no.1
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• pp.24-30
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• 2004

In this work the dynamic heat transfer occurring in a cable penetration fire stop system built in the firewall of nuclear power plants is three-dimensionally investigated to develop a test-simulator that can be used to verify effectiveness of the sealants. Here was carried out an experiment to observe the heat transfer in the cable penetration fire stop system made of DOW CORNING products. The dynamic heat transfer occurring in the fire stop system is formulated in a parabolic partial differential equation subjected to a set of initial and boundary conditions. And it was modeled, simulated, and analyzed. The simulation results were illustrated in three-dimensional graphics and were compared with experimental data. Through the simulations, it was shown clearly that the temperature distribution was influenced very much by the number, position, and temperature of the cable streams. It also was found that the dynamic heat transfer through the cable streams was one of the most dominant factors, and the feature of heat conduction could be understood as an unsteady-state process. It is certain that these numerical results are useful for making a performance-based design for the cable penetration fire stop system.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.50-58
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• 2005

Recently, the imaging of geological structures beneath water-covered areas has been in great demand because of numerous tunnel and bridge construction projects on river or lake sites. An electrical resistivity survey can be effective in such a situation because it provides a subsurface image of faults or weak zones beneath the water layer. Even though conventional resistivity surveys in water-covered areas, in which electrodes are installed on the water bottom, do give high-resolution subsurface images, much time and effort is required to install electrodes. Therefore, an easier and more convenient method is sought to find the strike direction of the main zones of weakness, especially for reconnaissance surveys. In this paper, we investigate the applicability of the streamer resistivity survey method, which uses electrodes in a streamer cable towed by ship or boat, for delineating a fault zone. We do this through numerical experiments with models of water-covered areas. We demonstrate that the fault zone can be imaged, not only by installing electrodes on the water bottom, but also by using floating electrodes, when the depth of water is less than twice the electrode spacing. In addition, we compare the signal-to-noise ratio and resolving power of four kinds of electrode arrays that can be adapted to the streamer resistivity method. Following this numerical study, we carried out both conventional and streamer resistivity surveys for the planned tunnel construction site located at the Han River in Seoul, Korea. To obtain high-resolution resistivity images we used the conventional method, and installed electrodes on the water bottom along the planned route of the tunnel beneath the river. Applying a two-dimensional inversion scheme to the measured data, we found three distinctive low-resistivity anomalies, which we interpreted as associated with fault zones. To determine the strike direction of these three fault zones, we used the quick and convenient streamer resistivity.

• Progress in Medical Physics
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• v.15 no.1
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• pp.1-8
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• 2004

Patient dose verification is one of the most Important responsibilities of the physician in the treatment delivery of radiation therapy. For the task, it is necessary to use an accurate dosimeter that can verify the patient dose profile, and it is also necessary to determine the physical characteristics of beams used in intensity modulated radiation therapy (IMRT) The Beam Intensity Scanner (BInS) System is presented for the dosimetric verification of the two dimensional photon beam. The BInS has a scintillator, made of phosphor Terbium-doped Gadolinium Oxysulphide (Gd$_2$O$_2$S:Tb), to produce fluorescence from the irradiation of photon and electron beams. These fluoroscopic signals are collected and digitized by a digital video camera (DVC) and then processed by custom made software to express the relative dose profile in a 3 dimensional (3D) plot. As an application of the BInS, measurements related to IWRT are made and presented in this work. Using a static multileaf collimator (SMLC) technique, the intensity modulated beam (IMB) is delivered via a sequence of static portals made by controlled leaves. Thus, when static subfields are generated by a sequence of abutting portals, the penumbras and scattered photons of the delivered beams overlap in abutting field regions and this results in the creation of “hot spots”. Using the BInS, inter-step “hot spots” inherent in SMLC are measured and an empirical method to remove them is proposed. Another major MLC technique in IMRT, the dynamic multileaf collimator (DMLC) technique, has different characteristics from SMLC due to a different leaf operation mechanism during the irradiation of photon and electron beams. By using the BInS, the actual delivered doses by SMLC and DMLC techniques are measured and compared. Even if the planned dose to a target volume is equal in our experimental setting, the actual delivered dose by DMLC technique is measured to be larger by 14.8% than that by SMLC, and this is due to scattered photons and contaminant electrons at d$_{max}$.

• Quality Improvement in Health Care
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• v.1 no.2
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• pp.44-59
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• 1994

Medical consumers(patients) want evening-clinic because of busy work. For patient's convenience and improving service, hospital should accept it. Considering payment system and patient's demand, personnel expenses, hospital can not accept. The practice of shift system to accept patient's demand and hospital's economic aspect was made. To analysis the effect of the system and probability to alternative to evening clinic this study was done. This study was composed of basal study, intervention, evaluation of effect. The basal study were composed of studying demand on evening clinic, the number of beds, doctors employee, the time table of practice and work, and the number of patients at arrival time. The intervention composed of changing of practice time, changing of working time by the number of patients at arrival time, increasing of employee. The evaluation of effect were composed of evaluating the number of patient at time, the effect of shift system, the comparison of the number of in and out patients and questionnairing the practice of shift system. In the practice time at 2 shift system First team works 7-15 hours and Second team 12-20 hours. there are no lunch and supper time. At 18-20 hours the number of patients were 25-30. The number of patient a depart were 6-7. The number of out-patient increase in 13% and inpatient increase in 10% before the system. Doctors(100%), employee(94.6%), and patients(86.4%) approved this system. The advantage of this system were utilization of surplus time, lengthen the practice time, even distribution of patients and shortening of waiting time, rapid treatment of emergent patients. The disadvantage of this system were shortage of manpower, not all depart practice, continuity of practice, no lunch and supper time, irregular rounding. At present because of small Demanding on evening clinic, this shift system was economical. To succeed this study more effectively all depart in hospital participate. But because of economical reason it is impossible for hospital to do it. If the government assist the economic loss that all depart participate in this system it is very helpful for hospital to succeed in implementing this system more early.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.301-306
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• 2018

Urbanization causes urban floods and urban heat island in the summer, so it is necessary to understanding the changes of the thermal environment through urban climate and energy balance. This can be explained by the energy balance, but in urban areas, unlike the typical energy balance, the storage heat flux saved in the building or artificial land cover should be considered. Since the environment of each city is different, there is a difficulty in applying the method of retrieving the storage heat flux of the previous research. Especially, most of the previous studies are focused on the overseas cities, so it is necessary to study the storage heat retrieval suitable for various land cover and building characteristics of the urban areas in Korea. Therefore, the object of this study, it is to derive the regression formula which can quantitatively retrieve the storage heat using the data of the area where various surface types exist. To this end, nonlinear regression analysis was performed using net radiation and surface temperature data as independent variables and flux tower based storage heat estimates as dependent variables. The retrieved regression coefficients were applied to each independent variable to derive the storage heat retrieval regression formula. As a result of time series analysis with flux tower based storage heat estimates, it was well simulated high peak at day time and the value at night. Moreover storage heat retrieved in this study was possible continuous retrieval than flux tower based storage heat estimates. As a result of scatter plot analysis, accuracy of retrieved storage heat was found to be significant at $50.14Wm^{-2}$ and bias $-0.94Wm^{-2}$.