• Fire Science and Engineering
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• v.34 no.3
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• pp.141-149
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• 2020

The Korea Industrial Standards (KS) stipulates methods and test procedures for measuring the horizontal combustibility of cellular plastics exposed to small flames (KS M ISO 9772:2018) and recommendations regarding the magnetic digestion of extruded polystyrene insulation (XPS) for measurement results (KS M 3808:2020). Although products that are certified to conform to KS standards must have burning characteristics (self-extinguishing), they are incinerated and spread by welds at construction sites, causing significant human and property damages. In this study, XPS produced by five companies, certified by KS, and sold in the market were purchased and tested for ignition and diffusion caused by a weld bullion at a construction site. The results showed that the five products had differences in performance. Three out of the five products were found to be self-saturated, but the other two were easily ignited and diffused, making it difficult for them to be self-extinguishing. Based on the result of this experimental investigation in line with the KS regulations, all the three types of products, including two types of products that were incinerated through weld defects, were found to be non-self-extinguishing, as specified in KS M 3808.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.195-201
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• 2016

Eddy current testing (ECT) is commonly applied for the inspection of automated production lines of metallic products, because it has a high inspection speed and a reasonable price. When ECT is applied for the inspection of a metallic object having an uneven target surface, such as the spline gear of a spline shaft, it is difficult to distinguish between the original signal obtained from the sensor and the signal generated by a defect because of the relatively large surface signals having similar frequency distributions. To facilitate the detection of defect signals from the spline gear, implementation of high-order filters is essential, so that the fault signals can be distinguished from the surrounding noise signals, and simultaneously, the pass-band of the filter can be adjusted according to the status of each production line and the object to be inspected. We will examine the infinite impulse filters (IIR filters) available for implementing an advanced filter for ECT, and attempt to detect the flaw signals through optimization of system design parameters for detecting the signals at the system level.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1131-1139
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• 2020

The static analysis of the source code is to find the remaining security weaknesses for a wide range of source codes. The static analysis tool is used to check the result, and the static analysis expert performs spying and false detection analysis on the result. In this process, the amount of analysis is large and the rate of false positives is high, so a lot of time and effort is required, and a method of efficient analysis is required. In addition, it is rare for experts to analyze only the source code of the line where the defect occurred when performing positive/false detection analysis. Depending on the type of defect, the surrounding source code is analyzed together and the final analysis result is delivered. In order to solve the difficulty of experts discriminating positive and false positives using these static analysis tools, this paper proposes a method of determining whether or not the security weakness found by the static analysis tools is a spy detection through artificial intelligence rather than an expert. In addition, the optimal size was confirmed through an experiment to see how the size of the training data (source code around the defects) used for such machine learning affects the performance. This result is expected to help the static analysis expert's job of classifying positive and false positives after static analysis.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.177-186
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• 2009

It is well-known that unregulated over-expression of foreign gene may have unwanted physiological or toxic effects in transgenic animals. To circumvent these problems, we constructed retrovirus vector designed to express the foreign gene under the control of the tetracycline-inducible promoter. However, gene expressions in the tetracycline-inducible expression system (Tet system) are not completely regulated but a little leaky due to the inherent defects in conventional Tet-based systems. A more tightly controllable regulatory system can be achieved when the advanced versions ($rtTA2^SM2$) of rtTA and a minimal promoter in responsive components (pTRE-tight) are used in combination therein. In this study, we tried to produce human thrombopoietin (hTPO) from various target cells and transgenic chickens using the retrovirus vector combined with Tet system. hTPO is the primary regulator of platelet production and has an important role in the survival and expansion of hematopoietic stem cells. In a preliminary experiment in vitro, higher hTPO expression and tighter expression control were observed in chicken embryonic fibroblast (CEF) cells. We also measured the biological activity of the hTPO using Mo7e cells whose proliferation is dependant on hTPO. The biological activity of the recombinant hTPO from CEF was higher than both its commercial counterpart and hTPO from other target cells. The recombinant retrovirus was injected beneath the blastoderm of non-incubated chicken embryos (stage X). Out of 138 injected eggs, 15 chicks hatched after 21 days of incubation. Among them, 8 hatched chicks were hTPO positive. When the Go transgenic chicken was fed doxycycline (0.5 mg per 1 gram of feed), a tetracycline derivative, hTPO concentration of the transgenic chicken blood was 200 ng/mL. Germline transmission of the transgene was confirmed in sperm of the Go transgenic roosters. These results are informative to establish transgenic chickens as bioreactors for the mass production of commercially valuable and biological active human cytokine proteins.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.668-675
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• 2017

To assess the physiological effects of Aruncus dioicus var. kamtschaticus extract on cytoxicity of a neuronal cell line, antioxidant activity, and neuroprotection against intensive glucose-induced oxidative stress were quantitated. Compared to the other fractions, the ethyl acetate fraction of Aruncus dioicus var. kamtschaticus (EFAD) showed the highest total phenolics and flavonoids. The 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay and malondialdehyde inhibitory effect test confirmed the superior antioxidant activity of EFAD. Moreover, EFAD also decreased the intracellular ROS level and suppressed neuronal cell death against intensive glucose- or $H_2O_2$-induced oxidative stress. Additionally, assessment of ${\alpha}$-glucosidase and acetylcholinesterase inhibitory activities revealed that EFAD was an effective inhibitor of ${\alpha}$-glucosidase and acetylcholinesterase. Finally, high-performance liquid chromatography analysis identified caffeic acid as the main ingredient of EFAD. Overall, these results suggest that the EFAD is a good natural source of biological compounds that counteract hyperglycemic neuronal defects.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.293-299
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• 2007

Intelligent pipeline inspection gauges (PIGs) are inspection vehicles that move along within a (gas or oil) pipeline and acquire signals (also called sensor data) from their surrounding rings of sensors. By analyzing the signals captured in intelligent PIGs, we can detect pipeline defects, such as holes and curvatures and other potential causes of gas explosions. There are two major data access patterns apparent when an analyzer accesses the pipeline signal data. The first is a sequential pattern where an analyst reads the sensor data one time only in a sequential fashion. The second is the repetitive pattern where an analyzer repeatedly reads the signal data within a fixed range; this is the dominant pattern in analyzing the signal data. The existing PIG software reads signal data directly from the server at every user#s request, requiring network transfer and disk access cost. It works well only for the sequential pattern, but not for the more dominant repetitive pattern. This problem becomes very serious in a client/server environment where several analysts analyze the signal data concurrently. To tackle this problem, we devise a fast in-memory cache manager, called T-Cache, by considering pipeline sensor data as multiple time-series data and by efficiently caching the time-series data at T-Cache. To the best of the authors# knowledge, this is the first research on caching pipeline signals on the client-side. We propose a new concept of the signal cache line as a caching unit, which is a set of time-series signal data for a fixed distance. We also provide the various data structures including smart cursors and algorithms used in T-Cache. Experimental results show that T-Cache performs much better for the repetitive pattern in terms of disk I/Os and the elapsed time. Even with the sequential pattern, T-Cache shows almost the same performance as a system that does not use any caching, indicating the caching overhead in T-Cache is negligible.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.528-543
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• 2005

Statement of problem: Repeated delivery and removal of abutment cause some changes such as wear, scratch or defect of hexagonal structure. It may increase the value of rotational freedom(RF) between hexagonal structures. Purpose: The purpose of this study was to evaluate surface changes and rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment after repeated delivery and removal under SEM and toolmaker's microscope. Materials and methods: Implant systems used for this study were 3i and Avana. Seven pail's of implant fixture, abutment and abutment screws for each system were selected and all fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. Each one was embedded beneath the platform of fixture. Surfaces of hexagonal structure before repeated closing and opening of abutment were observed using SEM and rotational freedom was measured by using toolmaker's microscope. Each abutment was secured to the implant future by each abutment screw with recommended torque value using a digital torque controller and was repeatedly delivered and removed by 20 times respectively. After experiment, evaluation for the change of hexagonal structures and measurement of rotational freedom were performed. Result : The results were as follows; 1. Wear of contact area between implant fixture and abutment was considerable in both 3i and Avana system. Scratches and defects were frequently observed at the line-angle of hexagonal structures of implant fixture and abutment. 2. In the SEM view of the external hexagon of implant fixture, the point-angle areas at the corner edge of hexagon were severely worn out in both systems. It was more notable in the case of 3i systems than in that of Avana systems. 3. In the SEM view of the internal hexagon of abutment, Gingi-Hue abutment of 3i systems showed severe wear in micro-stop contacts that were machined into the corners to prevent rotation and cemented abutment of Avana systems showed wear in both surface area adjacent to the corner mating with external hexagon of implant fixture. 4 The mean values of rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment were 0.48$\pm$0.04$^{\circ}$ in pre-tested 3i systems and 1.18$\pm$0.25$^{\circ}$ after test, and 1.80$\pm$0.04$^{\circ}$ in pre-tested Avana systems and 2.61$\pm$0.16$^{\circ}$ after test. 5. Changes of rotational freedom after test shouted statistical)y a significant increase in both 3i and Avana systems(P<0.05, paired t-test). 6. Statistically, there was no significant difference between amount of increase in the rotational freedom of 3i systems and amount of increase in that of Avana ones(P>0.05, unpaired t-test). Conclusion: Conclusively, it was considered that repeated delivery and remove of abutment by 20 times would not have influence on screw joint stability. However, it caused statistically the significant change of rotational freedom in tested systems. Therefore, it is suggested that repeated delivery and remove of abutment should be minimal as possible as it could be and be done carefully Additionally, it is suggested that the means or treatment to prevent the wear of mating components should be devised.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.13-44
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• 1982

1. Since long time ago, it has been talked about that soaking wood into water for a long time would be profitable for the decreasing of defects such as checking, cupping and bow due to the undue-shrinking and swelling. There are, however, no any actual data providing this fact definitly, although there are some guesses that water soluble extractives might effect on this problem. On the other hand, this is a few work which has been done about the effect of water soluble extractives upon the some physical properties of wood and that it might be related to the above mentioned problem. If man does account for that whether soaking wood into water for a long time would be profitable for the decreasing of defects due to the undue-shrinking and swelling in comparison with unsoaking wood or not, it may bring a great contribution on the reasonable uses of wood. To account for the effect of water soluble extractives upon physical properties of wood, this study has been made at the wood technology laboratory, School of Forestry, Yale university, under competent guidance of Dr. F. F. Wangaard, with the following three different species which had been provided at the same laboratory. 1. Pinus strobus 2. Quercus borealis 3. Hymenaea courbaril 2. The physical properties investigated in this study are as follows. a. Equilibrium moisture content at different relative humidity conditions. b. Shrinkage value from gre condition to different relative humidity conditions and oven dry condition. c. Swelling value from oven dry condition to different relative humidity conditions. d. Specific gravity 3. In order to investigate the effect of water soluble extractives upon physical properties of wood, the experiment has been carried out with two differently treated specimens, that is, one has been treated into water and the other into sugar solution, and with controlled specimens. 4. The quantity of water soluble extractives of each species and the group of chemical compounds in the extracted liquid from each species have shown in Table 36. Between species, there is some difference in quantity of extractives and group of chemical compounds. 5. In the case of equilibrium moisture contents at different relative humidity condition, (a) Except the desorption case at 80% R. H. C. (Relative Humidity Condition), there is a definite line between untreated specimens and treated specimens that is, untreated specimens hold water more than treated specimens at the same R.H.C. (b) The specimens treated into sugar solution have shown almost the same tendency in results compared with the untreated specimens. (c) Between species, there is no any definite relation in equilibrium moisture content each other, however E. M. C. in heartwood of pine is lesser than in sapwood. This might cause from the difference of wood anatomical structure. 6. In the case of shrinkage, (a) The shrinkage value of the treated specimen into water is more than that of the untreated specimens, except anyone case of heartwood of pine at 80% R. H. C. (b) The shrinkage value of treated specimens in the sugar solution is less than that of the others and has almost the same tendency to the untreated specimens. It would mean that the penetration of some sugar into the wood can decrease the shrinkage value of wood. (c) Between species, the shrinkage value of heartwood of pine is less than sapwood of the same, shrinkage value of oak is the largest, Hymenaea is lesser than oak and more than pine. (d) Directional difference of shrinkage value through all species can also see as other all kind of species previously tested. (e) There is a definite relation in between the difference of shrinkage value of treated and untreated specimens and amount of extractives, that is, increasing extractives gives increasing the difference of shrinkage value between treated and untreated specimens. 7. In the case of swelling, (a) The swelling value of treated specimens is greater than that of the untreated specimens through all cases. (b) In comparison with the tangential direction and radial direction, the swelling value of tangential direction is larger than that of radial direction in the same species. (c) Between species, the largest one in swelling values is oak and the smallest pine heartwood, there are also a tendency that species which shrink more swell also more and, on the contrary, species which shrink lesser swell also lesser than the others. 8. In the case of specific gravity, (a) The specific gravity of the treated specimens is larger than that of untreated specimens. This reversed value between treated and untreated specimens has been resulted from the volume of specimen of oven dry condition. (b) Between species, there are differences, that is, the specific gravity of Hymenaea is the largest one and the sapwood of pine is the smallest. 9. Through this investigation, it has been concluded that soaking wood into plain water before use without any special consideration may bring more hastful results than unsoaking for use of wood. However soaking wood into the some specially provided solutions such as salt water or inorganic matter may be dissolved in it, can be profitable for the decreasing shrinkage and swelling, checking, shaking and bow etc. if soaking wood into plain water might bring the decreasing defects, it might come from even shrinking and swelling through all dimension.

• Journal of Genetic Medicine
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• v.7 no.2
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• pp.125-132
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• 2010

Purpose: Preimplantation genetic diagnosis (PGD), also known as embryo screening, is a pre-pregnancy technique used to identify genetic defects in embryos created through in vitro fertilization. PGD is considered a means of prenatal diagnosis of genetic abnormalities. PGD is used when one or both genetic parents has a known genetic abnormality; testing is performed on an embryo to determine if it also carries the genetic abnormality. The main advantage of PGD is the avoidance of selective pregnancy termination as it imparts a high likelihood that the baby will be free of the disease under consideration. The application of PGD to genetic practices, reproductive medicine, and genetic counseling is becoming the key component of fertility practice because of the need to develop a custom PGD design for each couple. Materials and Methods: In this study, a survey on the contents of genetic counseling in PGD was carried out via direct contact or e-mail with the patients and specialists who had experienced PGD during the three months from February to April 2010. Results: A total of 91 persons including 60 patients, 49 of whom had a chromosomal disorder and 11 of whom had a single gene disorder, and 31 PGD specialists responded to the survey. Analysis of the survey results revealed that all respondents were well aware of the importance of genetic counseling in all steps of PGD including planning, operation, and follow-up. The patient group responded that the possibility of unexpected results (51.7%), genetic risk assessment and recurrence risk (46.7%), the reproduction options (46.7%), the procedure and limitation of PGD (43.3%) and the information of PGD technology (35.0%) should be included as a genetic counseling information. In detail, 51.7% of patients wanted to be counseled for the possibility of unexpected results and the recurrence risk, while 46.7% wanted to know their reproduction options (46.7%). Approximately 96.7% of specialists replied that a non-M.D. genetic counselor is necessary for effective and systematic genetic counseling in PGD because it is difficult for physicians to offer satisfying information to patients due to lack of counseling time and specific knowledge of the disorders. Conclusions: The information from the survey provides important insight into the overall present situation of genetic counseling for PGD in Korea. The survey results demonstrated that there is a general awareness that genetic counseling is essential for PGD, suggesting that appropriate genetic counseling may play a important role in the success of PGD. The establishment of genetic counseling guidelines for PGD may contribute to better planning and management strategies for PGD.