• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.81-87
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• 2006

Purpose: Few researches have been peformed on the dose distribution of the moving organ for radiotherapy so far. In order to simulate the organ motion caused by respiratory function, multipurpose phantom and moving device was used and dosimetric measurements for dose distribution of the moving organs were conducted in this study. The purpose of our study was to evaluate how dose distributions are changed due to respiratory motion. Materials and Methods: A multipurpose phantom and a moving device were developed for the measurement of the dose distribution of the moving organ due to respiratory function. Acryl chosen design of the phantom was considered the most obvious choice for phantom material. For construction of the phantom, we used acryl and cork with density of $1.14g/cm^3,\;0.32g/cm^3$ respectively. Acryl and cork slab in the phantom were used to simulate the normal organ and lung respectively. The moving phantom system was composed of moving device, moving control system, and acryl and cork phantom. Gafchromic film and EDR2 film were used to measure dose ditrbutions. The moving device system may be driven by two directional step motors and able to perform 2 dimensional movements (x, z axis), but only 1 dimensional movement(z axis) was used for this study. Results: Larger penumbra was shown in the cork phantom than in the acryl phantom. The dose profile and isodose curve of Gafchromic EBT film were not uniform since the film has small optical density responding to the dose. As the organ motion was increased, the blurrings in penumbra, flatness, and symmetry were increased. Most of measurements of dose distrbutions, Gafchromic EBT film has poor flatness and symmetry than EDR2 film, but both penumbra distributions were more or less comparable. Conclusion: The Gafchromic EBT film is more useful as it does not need development and more radiation dose could be exposed than EDR2 film without losing film characteristics. But as response of the optical density of Gafchromic EBT film to dose is low, beam profiles have more fluctuation at Gafchromic EBT. If the multipurpose phantom and moving device are used for treatment Q.A, and its corrections are made, treatment quality should be improved for the moving organs.

• The Korean Journal of Physiology
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• v.9 no.1
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• pp.13-22
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• 1975

From the study of movements of $Ca^{++}$ in frog cardiac muscle, Niedergerke (1963) postulated that $Ca^{++}$ necessary for the cardiac contraction is stored in a specific pool. Langer et al (1967) and DeCaro (1967) also found a close relationship between the change of $Ca^{++}$ flux kinetics and the change of contractile force. According to the studies of several investigators, Ca II (Bailey and Dressel 1968) or phase I and II (Langer 1965, Langer et al 1967, 1971) in the $Ca^{++}$ washout curve was associated with cardiac contractility. This investigation was aimed to elucidate the anatomical region of the contractile active $Ca^{++}$ pool. At the same time, it was assumed in this study that $Ca^{++}$ in the sarcoplasmic reticulumn represents one of the major intracellular $Ca^{++}$ pool and cardiac contractility was also dependent on the intracellular $Ca^{++}$ concentration. Consequently, this experiment was performed at different temperatures to activate to activate inhibit the deactivating process of activated $Ca^{++}$ in the intracellular space to see if changes in the contractility decay curve existed at different temperatures. The isolated hearts of rabbits and turtles (Amyda maackii) were attached to the perfusion apparatus according to the method employed by Bailey and Dressel (1968). The isolated hearts were initally perfused with a full Ringer solution containing 2 mg/ml of inulin for 1 hr, and then $Ca^{++}$ and inulin-free Ringer solution was perfused while the isometric tension was recorded and a serial sample of perfusion fluid dripping from the cardiac apex was collected for 10 sec throughout experimental period. The above procedure was performed at $23^{\circ}C$, $30^{\circ}C$ and $38^{\circ}C$ on the rabbit heart and $10{\sim}13^{\circ}C$, $10^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$ on the turtle heart. After determination of $Ca^{++}$ and inulin concentration of the samples, the $Ca^{++}$, inulin washout curve and the contractile tensin decay curve were analysed according to the method of Riggs (1963). The results were summarized as follows; 1. In the rabbit heart, there are 2 inulin compartments, 3 $Ca^{++}$ compartments and sing1e exponential decay of contractile tension. In the turtle heart, there are $1{\sim}2$ inulin compartments, $1{\sim}2$ $Ca^{++}$ compartments and $1{\sim}2$ phases of contractile tension decay. The fact that the inulin space was divided into 3 compartments in the washout curve in these hearts indicates the presence of heterogeneity in cardiac perfusion, i.e., overfused and underperfused area. 2. Ca I a9d Ca II in these hearts were found to have $Ca^{++}$ in the ECF compartments because their half times in the washout curves were far smaller than those of the inulin washout curves in the rabbit heart and similar to those of the inulin washout curves in the turtle heart. Ca III in the rabbit heart may have originated from the intracellular $Ca^{++}$ store. But no Ca III in the turtle heart was found. This may be due to the fact that the iutracellular $Ca^{++}$ pool in the turtle heart was too small to detect using this experimental procedure since sarcoplasmic reticulumn in the turtle heart is poorly developed. 3. In the rabbit heart, there were no chages in the half time of Ca I, Ca II, inulin I and inulin II at different temperatures, but the half time of Ca III was significantly prolonged at lower temperatures, and the half time of the contractile tension decay tended to be prolonged at lower temperatures but this was not significant. In the turtle heart, there were no changes in the half time of Ca I, Ca II, inulin 1, inulin II and phase I of the contractile tension decay at different temperatures, but the half time of phase II of the contractile tension decay was significantly prolonged at lower temperatures. This finding indicates that intracellu!ar $Ca^{++}$ in these hearts was also responsible particulary for maintaining the cardiac contractility at the lower temperatures. 4. The half times of contractile tension decay were shorter than those of Ca II in the $Ca^{++}$ washout curves in both animal hearts. According to the above results it was shown that $Ca^{++}$ in ECF is primarily and $Ca^{++}$ in the intracellular space is partially associated with the cardic contractility.

• The Korean Journal of Physiology
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• v.18 no.1
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• pp.81-96
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• 1984

As the crippled persons work mostly in a sitting position and would be engaged in a foot-pressing job, it is necessary to assess their degree of participation of important muscles in various modes of foot activities. In this regard, it deems to be urgent to establish the reference standards for healthy persons. The present study has been undertaken to determine the degree of participation of the M. tibialis anterior, M. gastrocnemius and M. soleus in heel pressing, foot-flat pressing and forefoot pressing motion under varying forces, and in order to compare the electrical activities of three muscles with each other, and to analyse the time sequence between force and appearance or disappearance of EMG recording. Sixty-three healthy young women ranging from age of 18 to 23 were examined. The results obtained were as follows: 1. Participation of three muscles in foot movement under varying forces: A) Both gastrocnemius muscles or left soleus muscle did not contribute to heel pressing motion. Activity of both tibialis anterior muscles was the greatest among three muscles at heel pressing motion and the degree of their activities was proportional to force. B) Activities of left tibialis anterior muscle and both gastrocnemius muscles were negligible under 3 kg force at foot-flat pressing movement. Left gastrocnemius muscle did not contribute to foot-flat pressing under 6 or 9 kg force. Although activities of both soleus muscles and both tibialis anterior muscles were small, the degree of their activities increased with force at foot-flat pressing movement. C) Activities of both tibialis anterior muscles were negligible under 3 kg force at forefoot pressing motion. Activity of both soleus muscles was the greatest among 3 muscles and the degree of their activities increased with force at forefoot pressing motion. Both tibialis anterior muscles participated in forefoot pressing motion with severe exertion. 2. Electrical activities by foot movement under varying forces : A) Electrical activities were prominent in both tibialis anterior muscles and the level of their activities was linear with force at heel pressing motion. The degree of participation of both soleus muscles was small at heel pressing motion. B) Electrical activity of tibialis anterior muscle was the greatest among 3 muscles at foot-flat pressing movement and was followed by that of soleus muscle. Level of electrical activities increased with force in left soleus muscle and right tibialis anterior muscle at foot-flat pressing movement. C) Electrical activity of both soleua muscles was the greatest among 3 muscles at forefoot pressing movement and that of tibialis anterior muscle was next to soleus muscle. Level of electrical activities was proportional to force in left tibialis anterior muscle, right gastrocnemius muscle and both soleus muscles at forefoot pressing movement. 3. Time between starting signal and initiation of contraction of heel pressing and forefoot pressing motion in 3 muscles was longer than that of foot-flat pressing movement. Time of relaxation in 3 muscles was longer than that of contraction under varying forces. EMG recording appeared before initiation of contraction in both tibialis anterior muscles at heel pressing motion and in both soleus muscles at forefoot pressing movement under varying forces. Time of initiation of contraction was similar in both sides of tibialis anterior muscles under varying forces and time of onset of contraction at foot-flat pressing motion was the shortest. 4. Forefoot pressing movement would be encouraged in paralysis of tibialis anterior muscle, while heel pressing motion would be encouraged in paralysis of triceps surae muscle.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.149-156
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• 2016

Measurement of cardiac blood flow using the magnetic resonance imaging has been limited due to breathing and involuntary movements of the heart. The present study attempted to improve the accuracy of cardiac blood flow testing through phase contrast magnetic resonance imaging by presenting the adequate breathing method and imaging variables by comparing the measurement values of cardiac blood flow. Each was evaluated by comparing the breath hold retrospective 1NEX and non breath hold retrospective 1-3NEX in the ascending aorta and descending aorta. As a result, the average blood flow amount/velocity of the breath hold retrosepctive 1NEX method in the ascending aorta were $96.17{\pm}19.12ml/sec$, $17.04{\pm}4.12cm/sec$ respectively, which demonstrates a statistically significant difference(p<0.05) with the non-breath hold retrospective method 1NEX of $72.31{\pm}13.27ml$ and $12.32{\pm}3.85$. On the other hand, the average 2NEX blood flow and mean flow velocity is $101.90{\pm}24.09$, $16.84{\pm}4.32$, 3NEX $103.06{\pm}25.49$, $16.88{\pm}4.19$ did not show statistically significant differences(p>0.05).The average blood flow amount/ velocity of the breath hold retrospective 1NEX method in the descending aorta were $76.68{\pm}19.72ml/s$, and $22.23{\pm}4.8$, which did not demonstrate a significant difference in comparison to non-breath hold retrospective method 1-3 NEX. Therefore, the non breath hold retrospective method does not significantly differ in terms of cardiac blood flow in comparison with the breath hold retrospective method in accordance with the increase of NEX, so pediatric patients or patients who are not able to breathe well must have the diagnostic value of their cardiac blood flow tests improved.

• Journal of the Korean Society of School Health
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• v.7 no.1
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• pp.45-55
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• 1994

The purpose of this study is to contribute to improvement of educational environment by analysing all problems related to environment around the school. To accomplish this purpose, this study was carried out by examining the problems in controlling the areas required for cleanup with 220 teachers in charging the cleanup duties of the primary and secondary schools in Taegu between June 1 and July 15, 1993 and by actually surveying the prejudical business stores around 72 primary schools between August 10 and September 20, 1993. Although most teachers answered to the questionnaires that it is necessary to cleanup the bad environment around the school, the duties of its cleanup tend not to be considered as an important matter. The teachers considered that the most prejudical business store around the school is totally the game room, and in such order as comic books' store, liquor selling shop and causing noise and pollution. 57.3% of total respondents answered that the present cleanup movements have resulted in failure mostly because of both supervising authorities' careless promotion and store owners' excessive commercial transactions. The result of actual survey in environmental and sanitary cleanup area around 72 primary schools showed that the greatest number of 1,258 prejudical stores was the video tapes shop, and then in such order as lodgings, and game rooms, while the number of prejudical store by the schools was 17.5 stores per school on the average which showed a various distribution from zero to 77 places. In general, these prejudical stores were mainly located around the schools in Jung-gu and Seo-gu areas. In addition, it was shown that the more the number of students, the more the number of the prejudical stores. In order to improve the environment around the school, it is necessary to strictly carry out the zoning system relating to the usage of land, to strongly restrict the stores without permit and abnormal stores and to establish the basis asking the city development authorities to go through the environmental evaluation. Moreover, it is absolutely required to make efforts to establish the national right sense of education, and to closely cooperate with the related authorities.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.149-158
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• 1996

Purpose : To get an accute steepness of dose gradients at outside the target volume in intracranial lesion and a less limitation of beam selection avoiding the high dose at normal brain tissue, this Photon Knife Radiosurgery System was developed in order to provide the three-dimensional dose distribution through the reconstruction of CT scan and the combined stereotactic trans-multiarc beam mode based on linear accelerator photon beam. Materials and methods : This stereotactic radiosurgery, Photon Knife based on linear accelerator photon beam was provided the non-coplanar multiarc and trans-multiarc irradiations. The stereotactic trans-multiarc beam mode can be obtained from the patient position in decubitus. This study has provided the 3-dimensional isodose curve and anatomical structures with the surface rendering technique. The dose distribution from the combined two trans-multiarcs (2M 2TM) was compared to that of four non-coplanar multiarcs (4M) with same collimator size of 25 mm in a diameter and total gantry movements. Results : In this study, it shows that the dose distributions of stereotactic beam mode are significantly depended on the selected couch and gantry angle in same collimator size. Practical dose distribution of combined stereotactic trans-multiarc beam has shown a more small rim thickness than that of the non-coplanar multiarc beam mode in axial, sagittal and coronal plane in our study. 3-Dimensional dose line displayed with surface rendering of irregular target shape is helpful to determine the target dose and to predict the prognosis in follow-up radiosurgery. Conclusions : 3-Dimensional dose line displayed with surface rendering of irregular target shape is essential in stereotactic radiosurgery. This combined stereotactic trans-multiarc beam has shown a less limitation of the selection couch and gantry beam angles for the target surrounding critical organs. It has shown that the dose distribution of combined trans-multiarc beam greatly depended on the couch and gantry angles. In our experiments, the absorbed dose has been decreased to $27%$ / mm in maximum at the interval of $50\%$ to $80\%$ of isodose line.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.677-697
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• 1995

The analysis of long- period sea level variations with tidal record data around Korea, Japan, and Russia shows that about half of the variations are due to atmospheric influences. The sea level variation by water movements is the largest in the coasts along the Tsushima Current, and becomes smaller in the distant areas. It suggests that the sea level varications are related with the Tsushima Current. The effect of sea level variations to ocean circulation has been studied with a numerical model allowing barotropic sea level fluctuations, like the result with GCM (Semtner) model by Pang et al.(1993), the present model also shows that waters basically flow along isobaths over the last China Sea after geostyophic adjustment around Taiwan. However, barotropic sea level fluctuation makes the basic circulation in the Yellow Sea, which waters flow into the central Yellow Sea and out along the west coast of the Korean Peninsula. Besides this, barotropic sea level fluctuation makes long period waves over the shelf area as the Kuroshio varies. By the waves, the basic circulation in the Yellow Sea is disturbed, so that the flow pattern of oppositely flowing into the Yellow Sea along the west roast of the Korean Peninsula appears. In the Yellow Sea circulation, it seems that northwest winds strengthen the basic circulat ion In winter, and southeast winds strengthen the disturbed circulation in summer. Another point appeared by the long period wave is that the Tsushima Current possibly originates in different areas. There have been two opposing argues on the area in which the Tsushima Current originates the southwest sea of Kyushu Island and the adjacent sea of Taiwan. Through this study, we found that both of them seem to be important areas for the origin of the Tsushima Current, and one of them is possibly strengthened by long period waves. The long period waves given by the variation of the Kuroshio Current in the adjacent sea of Taiwan propagate to the Korea Strait as forced waves. The wave continuously propagates to the last Sea through the eastern channel, but reflects in the western channel due to bottom topography. The reflected waves propagate southwestward along the last China Sea as free waves and determine the sea level variations with forced waves.

• The korean journal of orthodontics
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• v.29 no.1 s.72
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• pp.113-127
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• 1999

The purpose of this study is to investigate the stability of counterclockwise rotation of mandible by sagittal split ramus osteotomy to correct the skeletal Class III malocclusion with anterior open bite. Twenty five skeletal Class III open bite patients(mean age 20.6 years) who were treated by the sagittal split ramus osteotonues with rigid fixation were examined in this study. Cephalometric radiographs were taken for each Patients Preoperative(T1), ewly Postoperative(T2), and late postoperative Period(T3). Mean postoperative period was 8.0 months. Cephalometric analysis was done and data from T1, T2, and T3 were analyzed statistically by Paired t-test and Pearson correlation analysis. The following results were obtained. 1. Mandibular plane angle decreased $2.9^{\circ}$ and mandibular occlusal plane angle related to SN Plane decreased $2.7^{\circ}$ after orthognathic surgery(T2). At 6 months after orthognathic surgery(T3), mandibular plane angle increased $1.0^{\circ}$, but mandibular occlusal plane angle did not changed. 2. The amount of horizontal relapse long time after orthognathic surgery(T3) was 1.6 mm at B point and it was $22\%$ of the total posterior movements. There was no vertical relapse in the anterior facial height. 3. The related factor with horizontal relapse at late postoperative period was mandibular plane angle(p<0.01). The related factors with decreasing posterior facial height were amount of mandibular setback(p<0.01), increasing of mandibular ramus height(p<0.01), and decrease of the mandibular plane angle during operation(p<0.01). 4. There was no relationship between the amount of changes in mandibular occlusal plan angle during operation and the amount of relapse after surgery.

• KDI Journal of Economic Policy
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• v.12 no.4
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• pp.21-46
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• 1990

This paper, a sequel to Yoo and Lee (1990), attempts to investigate the interindustry determinants of technical efficiency in Korea's manufacturing industries, and also to conduct an exploratory analysis on the stability of technical efficiency over time. The hypotheses set forth in this paper are most found in the existing literature on technical efficiency. They are, however, revised and shed a new light upon, whenever possible, to accommodate any Korea-specific conditions. The set of regressors used in the cross-sectional analysis are chosen and the hypotheses are posed in such a way that our result can be made comparable to those of similar studies conducted for the U.S. and Japan by Caves and Barton (1990) and Uekusa and Torii (1987), respectively. It is interesting to observe a certain degree of similarity as well as differentiation between the cross-section evidence on Korea's manufacturing industries and that on the U.S. and Japanese industries. As for the similarities, we can find positive and significant effects on technical efficiency of relative size of production and the extent of specialization in production, and negative and significant effect of the variations in capital-labor ratio within industries. The curvature influence of concentration ratio on technical efficiency is also confirmed in the Korean case. There are differences, too. We cannot find any significant effects of capital vintage, R&D and foreign competition on technical efficiency, all of which were shown to be robust determinants of technical efficiency in the U.S. case. We note, however, that the variables measuring capital vintage effect, R&D and the degree of foreign competition in Korean markets are suspected to suffer from serious measurement errors incurred in data collection and/or conversion of industrial classification system into the KSIC (Korea Standard Industrial Classification) system. Thus, we are reluctant to accept the findings on the effects of these variables as definitive conclusions on Korea's industrial organization. Another finding that interests us is that the cross-industry evidence becomes consistently strong when we use the efficiency estimates based on gross output instead of value added, which provides us with an ex post empirical criterion to choose an output measure between the two in estimating the production frontier. We also conduct exploratory analyses on the stability of the estimates of technical efficiency in Korea's manufacturing industries. Though the method of testing stability employed in this paper is never a complete one, we cannot find strong evidence that our efficiency estimates are stable over time. The outcome is both surprising and disappointing. We can also show that the instability of technical efficiency over time is partly explained by the way we constructed our measures of technical efficiency. To the extent that our efficiency estimates depend on the shape of the empirical distribution of plants in the input-output space, any movements of the production frontier over time are not reflected in the estimates, and possibilities exist of associating a higher level of technical efficiency with a downward movement of the production frontier over time, and so on. Thus, we find that efficiency measures that take into account not only the distributional changes, but also the shifts of the production frontier over time, increase the extent of stability, and are more appropriate for use in a dynamic context. The remaining portion of the instability of technical efficiency over time is not explained satisfactorily in this paper, and future research should address this question.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.4
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• pp.11-22
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• 2017

A plaza represents the identity of a city, and that reveals a plaza's importance. Gwanghwamun Plaza and Seoul Plaza are two representative plazas where the citizens can freely express their opinions. Many major plazas in the center of Seoul were built under the Japanese occupation. Among these, the plaza of Joseon Bank has different characteristics than Gwanghwamun Plaza and Seoul Plaza. Even though this plaza was built in the center of the commercial, administrational, and cultural district during the Japanese colonial period, the research on this plaza has been limited. This study was conducted to verify the features of this plaza by analyzing its construction and transformation during the Japanese colonial period. The study's results outline how the plaza was constructed by the Japanese administration. The intention of the government is shown by the fact that it purchased land parcels and held a design competition. In the 1910s, the government purchased seven parcels of land during the expansion of roads as the place for the plaza. During the late 1930s, the government accepted a traffic circle to regulate the traffic and eliminate the conflict between crossing movements. In 1939, a fountain was built in the plaza's center, and its design was selected through a design competition. It was planned as a square, but gradually turned into a rotary. Furthermore, the plaza was a landmark and symbol of the power and modernity of Japan. As the main modal point of public transportation, the plaza became surrounded with largescale Western-style buildings, commercial advertising, and neon signs. The plaza became a place where people could experience the modern city. These spectacular displays showed that Japanese imperialism was perceived as a strange and peculiar landscape to the majority of Korean citizens. This study investigates the history and characteristics of the plaza, focusing on its beginning as well as the transformation of its form. As to the limitations of the study, it does not consider political and economic contexts within the transformation of Seoul and in relation to this plaza. Instead, that research remains for a future study.