• Polymer(Korea)
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• v.27 no.3
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• pp.183-188
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• 2003

The dielectric constants of fluorine-containing epoxy resins, 2-diglycidylether of benzotrifluoride(FER)/4,4'-diamino-diphenyl methane (DDM) and diglycidylether of bisphenol-A (DGEBA)/DDM systems were evaluated by dielectric spectrometer. Glass transition temperature and thermal stability factors, including initial decomposed temperature, temperatures of maximum rate of degradation, and decomposition activation energy of the cured specimens were investigated by dynamic mechanical analysis and thermogravimetric analysis. For the mechanical properties of the casting specimens, the fracture toughness, flexural, and impact tests were performed, and their fractured surfaces were examined by scanning electron microscope. The dielectric constant of FER/DDM system was lower than that of commercial DGEBA/DDM system, and the mechanical properties of the cured specimens showed higher values than those of DGEBA/DDM system. This was probably due to the introduction of trifluoromethyl (CF$_3$) group into the side chain of the epoxy resins, resulting in improving the electric and mechanical properties of the epoxy cure system studied.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.61-67
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• 2020

In this paper, we calculated the warpage of bare substrates and chip attached substrates by using FEM (Finite Element Method), and compared and analyzed the effect of the chips' attachment on warpage. Also, the effects of layer thickness of substrates for reducing warpage were analyzed and the conditions of layer thickness were analyzed by signal-to-noise ratio of Taguchi method. According to the analysis results, the direction of warpage pattern in substrates can change when chips are attached. Also, the warpage decreases as the difference in the CTE (coefficient of thermal expansion) between the top and bottom of the package decreases and the stiffness of the package increases after chips are loaded. In addition, according to the impact analysis of design parameters on substrates where chips are not attached, in order to reduce warpage, the inner layers of the circuit layer Cu1 and Cu4 has be controlled first, and then concentrated on the thickness of the solder resist on the bottom side and the thickness of the prepreg layer between Cu1 and Cu2.

• The Korea Journal of Herbology
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• v.36 no.4
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• pp.1-7
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• 2021

Objective : As more and more people are interested in appearance in modern society, the increasing number of hair loss population can have an important impact on psychological and social problems such as depression and inappropriate interpersonal symptoms. Therefore, much research is being done on treatments for alopecia using herbal extracts with relatively few side effects. This study was investigated about the effect of Achyranthis Radix (AR) extract with ethanol solvent on hair growth. Methods : We determined the promoting efficacy of AR-ethanol extract compared with minoxidil (MNXD) on the growth of human hair dermal papilla cells (HDPCs). Cell viability was measured by MTT assay and cell proliferation was confirmed by cell cycle analysis from flow cytometry in HDPCs. Also, we monitored the safe concentration range through MTT assay. And protein expression of hair growth-related genes (insulin-like growth factor 1 (IGF-1), Wnt3a, Protein kinase B (Akt), Extracellular signal-regulated kinase (Erk)) was monitored by western blot. Results : On cell cycle analysis, the G2/M phase was higher than that of the DW group in AR ethanol extract group at 0.05 and 0.1 mg/㎖. All protein expression levels of HDPCs were increased in AR ethanol extract groups and the MNXD group, compared to the DW group, respectively. Conclusion : As mentioned above, AR extract increased cell proliferation and the protein expression of IGF-1, Wnt3a, Akt, Erk in HDPCs. These results suggest that AR ethanol extract has promoted hair growth and it might be potential hair growth supplement.

• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.9-19
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• 2019

The effects of artificial intelligence technology is social science research as research on the impact on industry and changes in daily life, etc. This means that developing 'emotion AI' will prepare 'next-generation 3D-vector-sensitive AI'. This suggests the main keywords of the tertiary AI decision-making power. Particularly important results will be achieved because of the importance of current unethical learning and the implementation of decision-making systems that reflect ethical value judgments. This is a data based simulation, and required (1)Available data, (2)the technology for the goal of simulation. This takes into account the general content of the intended simulation based research. Currently, existing researches focus on meaningful research motivation, but this study presents the direction of technology. So, empirical analysis is consistent with the decision-making power of each country vs. new technology firms for AI on ehtic responsibility. As a result, there is a need for a concrete contribution and interpretation that can be achieved for the ethic Responsibility, on the technical side of AI / ML. In AI decision making, analytic power of human empathy should be included tech own trust.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.3
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• pp.91-102
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• 2020

This study examined the apartment sale in lots system from 1960s to 1970s in Seoul from a historical perspective, with the focus on the concept and changes of pre-sale in lots system. By tracing back historical context and application of the system in that period through the analysis of the advertisements for apartment sale, we found out the hidden side of the apartment pre-sale in lots system from the public's point of view, and its impact and meaning on the formation of our current residential culture. In the 1960s and 1970s, the apartment sale in lots system based on the pre-sale in lots system formed strong seller's market and it has been the main reason for imposing the wrong residential awareness that led the public to recognize housing as a means of property growth. Even now, the current apartment sale in lots system remains to be a supplier-oriented one, and lots of people tend to regard housing as investment method. That is, this mechanism is not only still working but one of the fundamental causes of impoverishing our residential culture. It is necessary to reconsider the pre-sale in lots system and the apartment sale in lots system in relation to the public of housing.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.113-119
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• 2023

Despite the lifting of the mandatory wearing of masks, which was the main tool of the COVID-19 quarantine policy, we paid attention to the fact that some people are still wearing masks, and we wanted to clarify why people do not take off their masks. Through a survey in this regard, we were able to ascertain why some people continue to wear masks in a broader context. In this article, we directly and indirectly confirm the hidden side of citizens' continued wearing of masks by analyzing how the lifting of the mask-wearing obligation was reported in media articles that have a significant impact on citizens' behavior and attitude. Through this, it was confirmed that citizens continue to wear masks to protect themselves in an uncertain situation where the COVID-19 endemic has not been declared, despite the quarantine authorities' announcement of lifting the mandatory wearing. In a situation where crises such as COVID-19 are expected to repeat frequently in the future, it was concluded that it is important to build trust in the quarantine authorities.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.775-782
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• 2023

In order to overcome practical limitations in installing, managing and operating MRI machines with expensive equipment, this study developed and utilized virtual reality (VR) experience education by combining virtual reality (VR) with magnetic resonance imaging devices. The Students who experienced virtual reality-based educational systems were surveyed to identify possible side effects during the experience and self-directed learning ability and academic self-efficacy surveys were conducted to analyze the impact of virtual reality-based practice on learning. In the analysis of the self-directed learning ability survey there was no difference in the average between the student group who experienced education and the student group who did not but there was a significant difference in the average for each group. Virtual Reality-based practical education is expected to provide an efficient practice system by providing new learning methods and opportunities for education that can be repeated anytime, anywhere regardless of time and space.

• Journal of Auto-vehicle Safety Association
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• v.15 no.4
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• pp.88-94
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• 2023

The seating postures of passengers in the automated driving vehicle are possible in atypical forms such as rear-facing and lying down. It is necessary to improve devices such as airbags and seat belts to protect occupants from injury in accidents of the automated driving vehicle, and collision safety evaluation tests must be newly developed. The purpose of this study is to define representative types of head-on collision accidents to develop collision standards for autonomous vehicles that take into account changes in driving behavior and occupants' postures. 150 frontal collision cases remained by filtering (accident videos, images, AIS 2+, passenger car, etc…) and random sampling from approximately 320,000 accidents claimed by a major insurance company over the past 5 years. The most frequent accident type is a head-on collision between a vehicle going straight and a vehicle turning left from the opposite side, accounting for 54.7% of all accidents, and most of these accidents occur in permissive left turns. The next most common frontal collision is the center-lane violation by drowsy driving and careless driving, accounting for 21.3% of the total. For the two types above, data such as vehicle speed, contact point/area, and PDOF at the moment of impact are obtained through accident reconstruction using PC-Crash. As a result, two types of autonomous vehicle crash safety test scenarios are proposed: (1) a frontal oblique collision test based on the accident types between a straight vehicle and a left-turning vehicle, and (2) a small overlap collision test based on the head-on accidents of center-lane violation.

• Journal of Digital Convergence
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• v.11 no.2
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• pp.385-390
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• 2013

The meaning of things appeared in the frame vary according to how they look in a shot. Especially, position of frame shows how a form becomes a content in quality. This has a large impact on communication with audiences, reminds them a special feeling or atmosphere toward an object and plays a suggestive role for things that shows up. Thus, this study aimed to investigate how symbolisms appeared in the frame position are shown in the relation among characters' narrative, personality and conflict and understand correlation between frame position and characters accordingly. As an object to be analyzed, this study selected which was played with narratives of couples with different personalities. The results of analysis shows that it is deeply associated with couples' narrative, which means that trauma or the severance of relations between a couple is shown on left side, whereas a positive and future-oriented couple was mainly shown on right side and the rate of being situated in the center turned out to be high according to the power relations of love. Based on the comparison between symbolism appeared according to the frame position and narratives and traumas that various characters have, this study found that frame position is playing an important role in composing characters' personality.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.221-227
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• 2001

Objective : The therapeutic impact of tumor resection in glioblastomas is poorly defined and still questionable. Therefore, we conducted the current study to verify the role of tumor resection in the treatment of these highly malignant tumors. Methods : A retrospective study was performed(1990-1999) to compare the treatment results of surgical resection plus radiotherapy(130 patients) with those of stereotactic biopsy plus radiotherapy(19 patients) in glioblastomas. Only adult patients with supratentorial, de novo glioblastoma located in one lobe were included. Survival time/rate was analysed with Kaplan-Meier method, and prognostic variables were obtained from the univariate log-rank test and the multivariate Cox's proportional hazards model. Results : The resection group and the biopsy group did not differ in terms of age, gender, duration of symptoms, presenting symptoms, tumor location, tumor side, tumor size, and the frequency of midline shift. Patients in the biopsy group more often were found to have worse preoperative Karnofsky performance status(KPS)(p=0.001). On univariate analysis, age, KPS, and tumor side were associated with survival(p=0.0053, 0.0001, and 0.0331 respectively). Median survival time and 1-year survival rate were also statistically improved by tumor resection ; resection group - 13 months and 61.2%, and biopsy group - 8 months and 19.7%, respectively(p=0.0001). In patients with midline shift of the tumor, resection was highly effective comparing to biopsy(p=0.0001), but in patients without midline shift, external beam radiation alone was as effective as tumor resection(p=0.0605). Other prognostic variables did not affect survival. On multivariate analysis after variable selection, survival was independently associated with KPS(p=0.001), but not the surgical resection(p=0.2837). Even in biopsy group with midline shift of the tumor, survival rate was not different from that seen after tumor resection(p=0.3505). Conclusions : Radiotherapy alone was as effective as tumor resection plus radiotherapy in patients without midline shift of the tumor. Although there was not statistically significant, tumor resection looked like effective in patients with midline shift. For supratentorial, lobar glioblastoma patients without mass effect of the tumor, biopsy with radiotherapy is one of rational treatment strategies. We consider that tumor resection should be performed in patients with pretreatment midline shift.