• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.1 s.116
• /
• pp.62-75
• /
• 2007

This paper describes a shaped-beam antenna for increasing the antenna gain of a radiating element. The proposed antenna structure is composed of an exciting element and a multi-layered disk array structure(MDAS). The stack micro-strip patch elements were used as the exciter for effectively radiating the electromagnetic power to the MDAS over the broadband, and finite metallic disk array elements - which give the role of a director for shaping the antenna beam with the high gain - were finitely and periodically layered onto it. The efficient power coupling between the exciter and the MDAS should be carried out in such a way that the proposed antenna has a high gain characteristic. The design parameters of the exciter and the MDAS should be optimized together to meet the required specifications to meet the required specifications. In this study, a shaped-beam antenna with high gain was optimally designed under the operating conditions with a linear polarization and the frequency band of $9.6{\sim}10.4\;GHz$. Two methods constructed using thin dielectric film and dielectric foam materials respectively were also proposed in order to implement the MBAS of the antenna. In particular, through the computer simulation process, the electrical performance variations of the antenna with the MDAS realized by the thin dielectric film materials were shown according to the number of disk array elements in the stack layer. Two kinds of antenna breadboard with the MDAS realized with the thin dielectric film and dielectric foam materials were fabricated, but experimentation was conducted only on the antenna breadboard(Type 1) with the MDAS realized with the thin dielectric film materials according to the number of disk array elements in the stack layer in order to compare it with the electrical performance variations obtained during the simulation. The measured antenna gain performance was found to be in good agreement with the simulated one, and showed the periodicity of the antenna gain variations according to the stack layer number of the disk array elements. The electrical performance of the Type 1 antenna was measured at the center frequency of 10 GHz. As the disk away elements became the ten stacks, a maximum antenna gain of 15.65 dBi was obtained, and the measured return loss was not less than 11.4 dB within the operating band. Therefore, a 5 dB gain improvement of the Type 1 antenna can be obtained by the MDAS that is excited by the stack microstrip patch elements. As the disk array elements became the twelve stacks, the antenna gain of the Type 1 was measured to be 1.35 dB more than the antenna gain of the Type 2 by the outer dielectric ring effect, and the 3 dB beam widths measured from the two antenna breadboards were about $28^{\circ}$ and $36^{\circ}$ respectively.

• KDI Journal of Economic Policy
• /
• v.12 no.2
• /
• pp.51-79
• /
• 1990

Research on technical efficiency, an important dimension of market performance, had received little attention until recently by most industrial organization empiricists, the reason being that traditional microeconomic theory simply assumed away any form of inefficiency in production. Recently, however, an increasing number of research efforts have been conducted to answer questions such as: To what extent do technical ineffciencies exist in the production activities of firms and plants? What are the factors accounting for the level of inefficiency found and those explaining the interindustry difference in technical inefficiency? Are there any significant international differences in the levels of technical efficiency and, if so, how can we reconcile these results with the observed pattern of international trade, etc? As the first in a series of studies on the technical efficiency of Korea's manufacturing industries, this paper attempts to answer some of these questions. Since the estimation of technical efficiency requires the use of plant-level data for each of the five-digit KSIC industries available from the Census of Manufactures, one may consture the findings of this paper as empirical evidence of technical efficiency in Korea's manufacturing industries at the most disaggregated level. We start by clarifying the relationship among the various concepts of efficiency-allocative effciency, factor-price efficiency, technical efficiency, Leibenstein's X-efficiency, and scale efficiency. It then becomes clear that unless certain ceteris paribus assumptions are satisfied, our estimates of technical inefficiency are in fact related to factor price inefficiency as well. The empirical model employed is, what is called, a stochastic frontier production function which divides the stochastic term into two different components-one with a symmetric distribution for pure white noise and the other for technical inefficiency with an asymmetric distribution. A translog production function is assumed for the functional relationship between inputs and output, and was estimated by the corrected ordinary least squares method. The second and third sample moments of the regression residuals are then used to yield estimates of four different types of measures for technical (in) efficiency. The entire range of manufacturing industries can be divided into two groups, depending on whether or not the distribution of estimated regression residuals allows a successful estimation of technical efficiency. The regression equation employing value added as the dependent variable gives a greater number of "successful" industries than the one using gross output. The correlation among estimates of the different measures of efficiency appears to be high, while the estimates of efficiency based on different regression equations seem almost uncorrelated. Thus, in the subsequent analysis of the determinants of interindustry variations in technical efficiency, the choice of the regression equation in the previous stage will affect the outcome significantly.

• Restorative Dentistry and Endodontics
• /
• v.32 no.3
• /
• pp.208-221
• /
• 2007

The fracture toughness test is believed as a clinically relevant method for assessing the fracture resistance of the dentinal restoratives. The objectives of this study were to measure the fracture toughness $(K_{1C})$ and microtensile bond strength of dentin-resin composite interface and compare their relationship for their use in evaluation of the integrity of the dentin-resin bond. A minimum of six short-rod specimens for fracture toughness test and fifteen specimens for microtensile bond strength test was fabricated for each group of materials used. After all specimens storing for 24 hours in distilled water at $37^{\circ}C$, they were tensile-loaded with an EZ tester universal testing machin. Statistical analysis was performed using ANOVA and Tukey's test at the 95% confidence level, Pearson's coefficient was used to verify the correlation between the mean of fracture toughness and microtensile bond strength. FE-SEM was employed on fractured surface to describe the crack propagation. Fracture toughness value of Clearfil SE Bond (SE) was the highest, followed by Adper Single Bond 2 (SB), OptiBond Solo (OB), ONE-STEP PLUS (0S), ScotchBond Multi-purpose (SM) and there was significant difference between SE and other 4 groups (p < 0.05). There were, however, no significant difference among SB, OB, OS, SM (p > 0.05). Microtensile bond strength of SE was the highest, followed by SB, OB, SM, OS and OS only showed significant lower value (p < 0.05). There was no correlation between fracture toughness and microtensile bond strength values. FE-SEM examination revealed that dentin bonding agent showed different film thickness and different failure pattern according to the film thickness. From the limited results of this study, it was noted that there was statistically no correlation between K1C and ${\mu}TBS$. We can conclude that for obtaining the reliability of bond strength test of dentin bonding agent, we must pay more attention to the test procedure and its profound scrutiny.

• Journal of Sensor Science and Technology
• /
• v.10 no.1
• /
• pp.62-70
• /
• 2001

The ZnSe sample grown by chemical bath deposition (CBD) method were annealed in Ar gas at $45^{\circ}C$. Using extrapolation method of X-ray diffraction pattern, it was found to have zinc blend structure whose lattice parameter $a_o$ was $5.6687\;{\AA}$. From Hall effect, the mobility was likely to be decreased by impurity scattering at temperature range from 10 K to 150 K and by lattice scattering at temperature range from 150 K to 293 K. The band gap given by the transmission edge changed from $2.700{\underline{5}}\;eV$ at 293 K to $2.873{\underline{9}}\;eV$ at 10 K. Comparing photocurrent peak position with transmission edge, we could find that photocurrent peaks due to excition electrons from valence band, ${\Gamma}_8$ and ${\Gamma}_7$ and to conduction band ${\Gamma}_6$ were observed at photocurrent spectrum. From the photocurrent spectra by illumination of polarized light on the ZnSe thin film, we have found that values of spin orbit coupling splitting ${\Delta}so$ is $0.098{\underline{1}}\;eV$. From the PL spectra at 10K, the peaks corresponding to free bound excitons and D-A pair and a broad emission band due to SA is identified. The binding energy of the free excitons are determined to be $0.061{\underline{2}}\;eV$ and the dissipation energy of the donor -bound exciton and acceptor-bound exciton to be $0.017{\underline{2}}\;eV$, $0.031{\underline{0}}\;eV$, respectively.

• Journal of Animal Science and Technology
• /
• v.54 no.4
• /
• pp.267-274
• /
• 2012

The method of sexing based on differences in the rate of feather growth provides a convenient and inexpensive approach. The locus of feather development gene (K) is located on the Z chromosome and can be utilized to produce phenotypes that distinguish between the sexes of chicks at hatching. To establish the auto-sexing native chicken strains, this study analyzed the genotype frequency of the feathering in domestic chicken breeds. The method of classification of slow- and rapid-feathering chickens was also investigated. In the slow-feathering chicks, the coverts were either the same length or longer than the primary wing feathers at hatching. However, the rapid-feathering chicks had the primary wing feathers that were longer than the coverts. The growth pattern of tail feather also distinctively differed between the rapid- and slow-feathering chicks after 5-days. The accuracy of wing feather sexing was about 98% compared with tail sexing. In domestic chicken breeds, Korean Black Cornish, Korean Rhode Island Red, and Korean Native Chicken-Red had both dominant (K) and recessive ($k^+$) feathering genes. The other breeds of chickens, Korean Brown Cornish, Ogol, White Leghorn, Korean Native Chicken-Yellow, -Gray, -White and -Black had only the recessive feathering gene ($k^+$). Consequently, feather sexing is available using the domestic chicken breeds. Establishing the maternal stock with dominant gene (K-) and paternal stock with recessive gene ($k^+k^+$), the slow-feathering characteristic is passed from mothers to their sons, and the rapid-feathering characteristic is inherited by daughters from their fathers.

• Journal of the Society of Disaster Information
• /
• v.15 no.4
• /
• pp.469-478
• /
• 2019

Purpose: In this studies we examine the facilities damage characteristics caused by forest fire. Therefore, we surveyed damaged facilities from forest fire which was occurred on Goseong-Gun on march 28 in 2019.(damaged areas was 40ha) The types of facilities uses were house, public facility, warehouse and so on. 17 facilities were destroyed. The purpose of this study was to for establishing a disaster safety village in rural areas where damage from a similar type of disaster occurs repeatedly by conducting the consciousness survey targeting at experts and disaster safety officials in a local government. Method: We surveyed meteorological factors(temperature, wind speed, wind direction, humidity) per a minute for analyzing weather condition on Goseong-Gun when forest fire was occurred, spread and extinguished. And we surveyed forest fire risk factors(a slope degree, a slope direction, a geographical feature, a distance between forest and facility, main species, the existence of crown fire ignition, the direction of facility, the main material of building) around 10 damaged facilities. Finally, we analyzed damage pattern of facilities using meteorological factor and forest fire reisk fator Result: The weather condition of Kanseonng AWS (No.517) was high temperature, arid and strong wind, when the forest fire was occurred and spread. An average wind speed was 4.1m/s and the maximum wind speed was 11.6m/s. The main direction of wind was W(225~315°). Damaged facilities were located on the steep slope area and on the mountaintop. The forest density around facilities was high and main species was korean red pine. The crown fire was occurred in the forest around damaged facilities. The average distance was 13.5m from forest to facilities. When the main matarial of building was made by fire resistance materials (for example, rainforced concrete), the damage was slightly. on the other hand, when by flammable material (for example, a Sandwich Panel), the facilities were totally destroyed Conclusion: The results of this research which were the thinning around house, making a safety distance, the improvement of main material of building and etc, will be helpful for establishing a counter measure for a forest fire prevention of facilities in wild land urban interface

• Journal of radiological science and technology
• /
• v.28 no.1
• /
• pp.33-44
• /
• 2005

The objective of this study is to supply the good quality of experts the radiation industries in Korea and develop the major subject matter needed in the radiation industries and the curriculum in order to execute it for the variation of fields of employment at the department of radiation in the junior college and the development of the percentage of employment. In addition, this study is to improve the level of radiation experts engaged in the industries in quality, and it is to improve the social recognition of radiation rather negative now because of the development of radiation industry. As for the core results of this research, it was to suggest the detailed choice method curriculum proper to the service fields of radiation industries, but it may be subject to change due to each college's property and the educational objectives. From the result of this research above, it may be summed up as follows. First, as for the detailed curriculum by the service field, this study was to organize two subject matters: 1. the subject matter proper to the field of using the radiation, and 2. the subject matters proper to the safety control field of radiation. Second, as for the detailed curriculum by the pattern of industries, this study was to organize the four subject matters: 1. the subject matter needed in the manufactures, 2. the subject matter needed in the nondestructive testing industries, 3. the subject matter needed in the sales agencies, and 4. the subject matter needed in the laboratories. This study was to suggest the operational model about the curriculum in order to execute these subject matters. It could be executed as two methods below. First, one method is to execute the major systems by the medical field and industrial field in the third course at the department of radiation in the junior college now. Second, the other method is to make them specialize the industrial radiation in the Advanced Course(one year course) after the graduation of junior college. To operate these curricula successively it needs to assume the deeper research and the development of materials about the subject matters related to the nuclear radiation industries hereafter. In addition, it needs to solve the security of finance like the manpower of professor, space for practice, and the educational appliances, etc. needed in the operation of subject matters. Finally, the effect and result from the development or revision of college curriculum did not come out in a short time. It will require considerable time until the undergraduates at the department in the junior college finish a set of curriculum newly developed, and graduate the university, and can get the results while they engage in their works in the industrial sites. Accordingly, all the interested parties have to anticipate the results of this research with the patience in long-standing point of view. Also, this researcher considers it as it is willing to give them the continuous interest and support.

• Journal of Chest Surgery
• /
• v.31 no.5
• /
• pp.488-493
• /
• 1998

In the preoperative evaluation before coronary artery bypass surgery, review of the coronary arteriogram is the most important step. Expected "normal" lumen diameter at a given coronary anatomic location is a basis for quantative estimation of coronary disease severity that could be more useful than the traditional "percent stenosis". The distribution and number of major coronary artery branches are determinants of number of bypass grafts needed. We reviewed the coronary artery anatomy in 174 adult patients who revealed no coronary pathology in angiographic studies done from September 1994 to June 1996. Quantative analysis was done in all cases by a single person using a Computerized System (Arripro 35ⓡ). The results were follows; 1) The mean diametre of left main coronary artery was 4.45 mm(range 2.74~6.72). The pattern of branching was bifurcation in 67.24%, trifurcation in 28.74% and quadrifurcation in 4.02% of the patients. 2) The mean diametre of left anterior descending artery was 3.17 mm(range 2.10~5.85), 2.79 (range 1.55~5.59) and 2.17 mm(range 1.37~3.81) in the proximal, mid, and the distal portions, respectively. The number of diagonal branches of left anterior artery was from one to four(mode=2). 3) The mean diametre of proximal and distal left circumflex artery were 3.17mm(range 1.74~4.89) and 2.19 mm(range 1.21~4.46). The number of obtuse marginal branches of left circumflex artery is from one to six(mode 2). 4) The mean diametre of proximal and distal right coronary artery, the posterior descending artery and the largest posterolateral branch were mean 3.51 mm(range 2.07~5.67), 2.09 mm (range 1.42~3.60), 2.09 mm(range 1.02~3.60) and 2.30 mm(range 1.39~4.39). 5) The right coronary artery dominant was 163 cases(93.68%) of the total 174 cases. 6) The large significant acute marginal artery was visualized in more than half of the people. half of the people.

• Radiation Oncology Journal
• /
• v.29 no.1
• /
• pp.44-52
• /
• 2011

Purpose: To evaluate the outcomes and prognostic factors of postoperative radiotherapy (PORT) for patients with pathological stage III non-small-cell lung cancer (NSCLC) at a single institution. Materials and Methods: From 2000 to 2007, 88 patients diagnosed as having pathologic stage III NSCLC after curative resection were treated with PORT. There were 80 patients with pathologic stage IIIA and eight patients with pathologic stage IIIB in the AJCC 6th staging system. The majority of patients (n=83) had pathologic N2 disease, and 56 patients had single station mediastinal LN metastasis. PORT was administered using conventional technique (n=76) or three-dimensional conformal technique (n=12). The median radiation dose was 54 Gy (range, 30.6 to 63 Gy). Thirty-six patients received chemotherapy. Radiation pneumonitis was graded by the Radiation Therapy Oncology Group system, and other treatment-related toxicities were assessed by CTCAE v 3.0. Results: Median survival was 54 months (range, 26 to 77 months). The 5-year overall survival (OS) and disease free survival (DFS) rates were 45% and 38%, respectively. The number of metastatic lymph nodes was associated with overall survival (hazard ratio, 1.037; p-value=0.040). The 5-year locoregional recurrence free survival (LRFS) and distant metastasis free survival (DMFS) rates were 88% and 48%, respectively. Multiple stations of mediastinal lymph node metastasis was associated with decreased DFS and DMFS rates (p-value=0.0014 and 0.0044, respectively). Fifty-one relapses occurred at the following sites: 10 loco-regional, 41 distant metastasis. Grade 2 radiation pneumonitis was seen in three patients, and symptoms were well tolerated with anti-tussive medication. Grade 2 radiation esophagitis was seen in 11 patients. There were no grade 3 or more severe complications associated with PORT. Conclusion: Our retrospective data show that PORT for pathological stage III NSCLC is a safe and feasible treatment and could improve loco-regional control. The number of metastatic lymph nodes and stations of mediastinal lymph node metastasis were analyzed as prognostic factors. Furthermore, efforts are needed to reduce distant metastasis, which is a major failure pattern of advanced stage NSCLC.

• Korean Journal of Microbiology
• /
• v.38 no.3
• /
• pp.153-161
• /
• 2002

Sox4, a transcription factor, consists of three functional domains: an HMG-box domain as a DNA binding domain, serine rich region as a transactivation domain and glycine rich region (GRR), an unknown functional domain. Although Sox4 is known to be functionally involved in heart, B-cell and reproductive system development, its physiological function remains to be elucidated. We used pGEX expression system to develop a simple and rapid method for purifying Sox4 protein in suitable forms for biochemical studies of their functions. Unexpectedly, we observed that full-length Sox4 appears to be protease-sensitive during expression and purification in E. coli. To map the protease-sensitive site in Sox4, we generated various constructs with each of functional domains of Sox4 and purified as the GST-Sox4 fusion proteins using glutathione beads. We found that the specific cleavage site for the proteolytic enzyme, which exists in E. coli, is localized within the novel GRR of Sox4. Our study suggest that the GRR of Sox4 may a target for the cellular protease action and this cleavage in the GRR may be involved in regulating physiological function of Sox4. Additionally, our study may provide a useful method for investigating the proteolytic cleavage of the target molecule in E. coli.