• Journal of Korea Entertainment Industry Association
• /
• v.5 no.1
• /
• pp.122-126
• /
• 2011

In this paper, for the purpose of improving the future domestic train control systems and securing interoperability according to the global development trends of train control systems, we present the test results of interoperability between wayside train control system installed in existed line, and the onboard train control system. Due to the safety-critical characteristics of train systems, the site test in the section where the wayside equipment is installed, leads to a danger against safety. Therefore, by way of constructing a simulation environment of train control systems, we confirm the T/R data systems of the equipment for interoperability and test the interoperability by applying these systems to onboard equipment.

• Tuberculosis and Respiratory Diseases
• /
• v.74 no.2
• /
• pp.56-62
• /
• 2013

Background: The purpose of this study was to evaluate the relationship of pulmonary function impairment (PFI) and coronary artery calcification (CAC) by multi-detector computed tomography (MDCT), and the effect of pneumoconiosis on CAC or PFI. Methods: Seventy-six subjects exposed to inorganic dusts underwent coronary artery calcium scoring by MDCT, spirometry, laboratory tests, and a standardized questionnaire. CAC was quantified using a commercial software (Rapidia ver. 2.8), and all the subjects were divided into two categories according to total calcium scores (TCSs), either the non-calcified (<1) or the calcified (${\geq}1$) group. Obstructive pulmonary function impairment (OPFI) was defined as forced expiratory volume in one second/forced vital capacity ($FEV_1$/FVC, %)<70, and as $FEV_1$/FVC (%){\geq}70 and FVC<80 for restrictive pulmonary function impairment (RPFI) by spirometry. All subjects were classified as either the case (profusion${\geq}1/0$) or the control (profusion${\leq}0/1$) group by pneumoconiosis findings on simple digital radiograph. Results: Of the 76 subjects, 35 subjects (46.1%) had a CAC. Age and hypertension were different significantly between the non-calcified and the calcified group (p<0.05). Subjects with pneumoconiosis were more frequent in the calcified group than those in the non-calcified group (p=0.099). $FEV_1$/FVC (%) was significantly correlated with TCSs (r=-0.316, p=0.005). Subjects with OPFI tended to increase significantly with increasing of TCS (4.82, p=0.028), but not significantly in RPFI (2.18, p=0.140). Subjects with OPFI were significantly increased in the case group compared to those in the control group. Conclusion: CAC is significantly correlated with OPFI, and CAC and OPFI may be affected by pneumoconiosis findings.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.1
• /
• pp.43-49
• /
• 2018

PURPOSE. The purpose of this in vitro study is to examine the effects of a nano-structured alumina coating on the adhesion between resin cements and zirconia ceramics using a four-point bending test. MATERIALS AND METHODS. 100 pairs of zirconium bar specimens were prepared with dimensions of $25mm{\times}2mm{\times}5mm$ and cementation surfaces of $5mm{\times}2mm$. The samples were divided into 5 groups of 20 pairs each. The groups are as follows: Group I (C) - Control with no surface modification, Group II (APA) - airborne-particle-abrasion with $110{\mu}m$ high-purity aluminum oxide ($Al_2O_3$) particles, Group III (ROC) - airborne-particle-abrasion with $110{\mu}m$ silica modified aluminum oxide ($Al_2O_3+SiO_2$) particles, Group IV (TCS) - tribochemical silica coated with $Al_2O_3$ particles, and Group V (AlC) - nano alumina coating. The surface modifications were assessed on two samples selected from each group by atomic force microscopy and scanning electron microscopy. The samples were cemented with two different self-adhesive resin cements. The bending bond strength was evaluated by mechanical testing. RESULTS. According to the ANOVA results, surface treatments, different cement types, and their interactions were statistically significant (P<.05). The highest flexural bond strengths were obtained in nano-structured alumina coated zirconia surfaces (50.4 MPa) and the lowest values were obtained in the control group (12.00 MPa), both of which were cemented using a self-adhesive resin cement. CONCLUSION. The surface modifications tested in the current study affected the surface roughness and flexural bond strength of zirconia. The nano alumina coating method significantly increased the flexural bond strength of zirconia ceramics.

• Journal of Korean Society of Transportation
• /
• v.17 no.4
• /
• pp.71-84
• /
• 1999

The purpose of this study is to construct a dynamic traffic analysis model using the existing traffic flow theory in order to develope a dynamic traffic assignment technique. In this study the dynamic traffic analysis model was constructed using Daganzo's CELL TRANSMISSION THEORY which was considered more suitable to dynamic traffic assignment than the other traffic flow theories. We developed newly the diverging split module, the cost update module and the link cost function and defined the maximum waiting time decision function that Daganzo haven't defined certainly at his Papers. The output that resulted from the simulation of the dynamic traffic analysis model with test network I and II was shown at some tables and figures, and the analysis of the bottleneck and the HOV lane theory showed realistic outputs. Especially, the result of traffic assignment using the model doesn't show equilibrium status every time slice but showed that the average travel cost of every path maintains similarly in every time slice. It is considered that this model can be used at the highway operation and the analysis of traffic characteristics at a diverging section and the analysis of the HOV lane effect.

• Journal of the Korean Society for Railway
• /
• v.11 no.2
• /
• pp.139-144
• /
• 2008

Recent advances in embedded system technology have brought more dependence on automating train control. While much efforts have been reported to improve electronic hardware's safety, not so much systematic approaches to evaluate software's safety, especially for the vital software running on board train controllers. In this paper, we propose a new software tool to evaluate software safety for the train controller. We have reviewed requirements in the international standards and surveyed available tools in the market. From that, we identified necessary tests to meet the standards and proposed a tool that can be used during the whole software life cycle. We show the functional architecture and internal components of the tool. Our tool is unique in that it is a comprehensive tool specifically designed for software safety evaluation while other tools are not.

• Korean Journal of Head & Neck Oncology
• /
• v.23 no.1
• /
• pp.21-25
• /
• 2007

Background：Squamous cell carcinoma(SCC)of the palatine tonsils represents approximately 15-23% of all intraoral SCC. The most frequently reported risk factors for oropharyngeal cancer are smoking and alcohol. In a recent overview of HPV and tonsillar squamous cell carcinoma(TC), 51% contained HPV DNA, and HPV-16 being the most frequent type. We aimed to clarify whether HPV directly effects on the oncogenesis and biologic behavior of TC by comparison with infection prevalence, and physical status of virus. Material and Method：We used HPV genotyping DNA chip(Biocore, Korea, Seoul) arrayed by multiple oligonucleotide probes of L1 sequence of 26 types of HPV and HPV genotypes are identified by fluorescence scanner. The copy numbers of HPV E2 and E6 open reading frames(ORF) were assessed using a TaqMan-based 5'-exonuclease quantitative real-time PCR assay. The ratio of E2 to E6 copy numbers was calculated to determine the physical status of HPV-16 viral gene. Results：We observed a significant difference in HPV prevalence between 52 TCs and 69 CFTs(73.1% vs. 11.6%), and most of the HPVs were type 16(87.2%)and non-episomal(94.1%) state. Conclusions：This study regarding HPV infection prevalence and mechanism in the largest population of palatine tonsillar squamous cell carcinoma with chronic follicular tonsillitis revealed significant difference pf HPV prevalence between TC and CFT. Most of HPV were 16 type and integrated or mixed, HPV-16 integration could be directly related to tonsillar carcinogenesis.

• The Journal of Korean Academy of Prosthodontics
• /
• v.42 no.2
• /
• pp.133-141
• /
• 2004

Statement of problem : Porcelain restorations are widely used in restorative dentistry with a high degree of general success. However, porcelain is brittle and may fracture intraorally. Sometimes a repair may be attempted using composite resin and bonding system available. Color stability of porcelain repair resins affects esthetics and prognosis of prosthesis, so that provides important criteria for the choice of porcelain repair resins. Purpose : The purpose of this study was to investigate the color stability of composite resins used widely as porcelain repair system. Materials and method : Composite resins used for this study were Carisma(Kulzer, Germany), Tetric ceram(Ivoclar, Liechtenstein), Filtek Z250(3M, USA), and Arabesk Top(VOCO, Germany). Thirty disc-shaped specimens($10{\times}2mm$) were fabricated from each composite resin. Color changes of specimens after treatment using thermocycling system(KD-TCS30, Kwang-duk F.A. Korea) and after immersion in methylene blue(0.05% by Wt) were measured with colorimeter(Model Tc-6Fx, Tokyo Denshoku Co.) and obtained data were analyzed. Results and Conclusion: The results obtained from this study were as fo11ows. 1. The color change of Filtek Z250 was lesser than those of Tetric ceram and Arabesk Top after thermocycling (12000 times). 2. All of the composite resins in this study showed increase of color change according to increase of thermocycling frequency. 3. After treatment with methylene blue, the color change of Arabesk Top was greater than those of Carisma and Tetric ceram, and Tetric ceram was more stable than others.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.12
• /
• pp.90-95
• /
• 2006

The wall of thermal vacuum chamber which is used for the satellite thermal balance test doesn't absorb satellite's IR emission perfectly and reflects some part of that. It is estimated that small thermal vacuum chamber has relatively larger wall effect than the big one. The small thermal vacuum chamber is required for the small satellite test to reduce the test cost. A quantitative analysis was carried out to investigate the chamber wall effect. As a result, temperature errors caused by chamber wall effect was calculated, and the temperature data acquired in the thermal balance test have been compensated. By defining the optimized area ratio between chamber surface and satellite surface area, the baseline to be able to determine the minimum size of thermal vacuum chamber was established to minimize the wall effect. Also, theoretical analysis about transparent material coating which can reduce the chamber wall effect is conducted.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.12
• /
• pp.1222-1228
• /
• 2008

A small satellite, DubaiSat-1 FM(Flight Model), which is based on SI-200 standard bus platform and scheduled to be launched in 2008, is being developed by Satrec Initiative and EIAST(Emirates Institution for Advanced Science and Technology). The TCS(Thermal Control Subsystem) of DubaiSat-1 FM has been designed to mainly utilize passive thermal control in order to minimize power consumption, but the active control method using heaters has been applied to some critical parts. Also, thermal analysis has been performed for DubaiSat-1's mission orbit using a thermal analysis model. The thermal design is modified and optimized to satisfy the design temperature requirements for all parts according to the analysis result. The thermal control performance of DubaiSat-1 FM is verified by thermal vacuum space simulation, consisting of thermal cycling and thermal balance test. Also, to validate the thermal modeling of DubaiSat-1 FM, comparison of test results with analysis has been performed and model calibration has been completed.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.11
• /
• pp.921-930
• /
• 2013

Satrec Initiative successfully developed and verified a high-resolution electro-optical camera system, EOS-D Ver.1.0. We designed this system to give improved spatial and radiometric resolution compared with EOS-C series systems. The thermal control subsystem (TCS) of the EOS-D Ver.1.0 uses heaters to meet the opto-mechanical requirements during in-orbit operation and uses different thermal coatings and multi-layer insulation (MLI) blankets to minimize the heater power consumption. Also, we designed and verified a refocusing mechanism to compensate the misalignment caused by moisture desorption from the metering structure. We verified the design margin and workmanship by conducting the qualification level thermal vacuum test. We also performed the verification of thermal math model (TMM) by comparing with thermal balance test results. As a result, we concluded that it faithfully represents the thermal characteristics of the EOS-D Ver.1.0.