• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.2
• /
• pp.303-310
• /
• 2008

We fabricated hydrogenated amorphous silicon(a-Si:H) 140 nm thick film on a $180\;nm-SiO_2/Si$ substrate with an inductively-coupled plasma chemical vapor deposition(ICP-CVD) equipment at $250^{\circ}C$. Moreover, 30 nm-Ni film was deposited with a thermal-evaporator sequently. Then the film stack was annealed to induce silicides by a rapid thermal annealer(RTA) at $200{\sim}500^{\circ}C$ in every $50^{\circ}C$ for 30 minuets. We employed a four-point tester, high resolution X-ray diffraction(HRXRD), field emission scanning electron microscope(FE-SEM), transmission electron microscope(TEM), and scanning probe microscope(SPM) in order to examine the sheet resistance, phase transformation, in-plane microstructure, cross-sectional microstructure evolution, and surface roughness, respectively. We confirmed that nano-thick high resistive $Ni_3Si$, mid-resistive $Ni_2Si$, and low resistive NiSi phases were stable at the temperature of <300, $350{\sim}450^{\circ}C$, and >$450^{\circ}C$, respectively. Through SPM analysis, we confirmed the surface roughness of nickel silicide was below 12 nm, which implied that it was superior over employing the glass and polymer substrates.

• Journal of Wetlands Research
• /
• v.18 no.3
• /
• pp.324-329
• /
• 2016

Constructed wetlands are widely applied in urban and rural areas for various purposes such as pollutants reduction, acquisition of eco-spaces and habitats, flooding reduction, acquisition of water resources and environmental education. Since the design of constructed wetlands utilizes ecosystems, special consideration must be given to ecological mechanisms, environmental mechanisms and hydrological mechanisms. To ensure the sustainable functionality of constructed wetlands, it is necessary to achieve stable flow rate and velocity, and remove sediments to ensure sufficient space for detention. To enhance the efficiency of constructed wetland sedimentation basins, this study determined the optimal position for baffle installation, and applied Computational Fluid Dynamics (CFD) to the cross-sectional design of wetlands. CFD analysis revealed that the decrease in flow velocity with baffle installation enhanced the efficiency of sedimentation of particulate matters. Vertical baffles had higher sedimentation efficiency than those with an inclined angle. When vertical baffles were installed in the sedimentation basin of a hybrid constructed wetland to reduce non-point source pollutants in urban areas, the average flow velocity within the basin decreased by 10~30%, while the sedimentation efficiency improved by 1.3~1.5 times. The application of CFD to constructed wetlands is expected to improve the cost efficiency of designing hybrid constructed wetlands with high removal efficiency.

• Journal of Hospice and Palliative Care
• /
• v.15 no.4
• /
• pp.205-211
• /
• 2012

Purpose: This study was performed to identify the level of stress perceived by nurses who attend dying patients in the cancer care unit; their understanding regarding end-of-life care and related training needs. Methods: A cross-sectional descriptive study was conducted with 151 nurses stationed at the cancer care units of four general hospitals located in Seoul and Gyeonggi province in Korea. Data were collected using self-reported questionnaires and the response rate was 96%. The data were analyzed using t-test, ANOVA and Pearson's correlation analysis. SPSS 12.0 was used for data analysis. Results: Nurses experienced a high level of stress in the end-of-life care settings. Their understanding of end-of-life care was above the mid-point of the scale while their training needs for end-of-life care was relatively high. The more experienced the nurses were, the more stressed they were, particularly due to excessive workload. Nurses who served longer in the cancer unit tended to show greater needs for end-of-life care training. Conclusion: This study found nurses perform end-of-life care with a high level of stress but with insufficient understanding, and thus, showed great needs for related training. Such findings can be useful to develop an end-of-life care training program for nurses.

• Korean Journal of Community Nutrition
• /
• v.20 no.2
• /
• pp.129-140
• /
• 2015

Objectives: We examined the association between the adherence to dietary guidelines for breast cancer survivors and health-related quality of life in a cross-sectional study of Korean breast cancer survivors. Methods: A total of 157 women aged 21 to 79 years who had been diagnosed with stage I to III breast cancers according to the American Joint Committee on Cancer (AJCC) and had breast cancer surgery at least 6 months before the baseline were included. We used a Korean version of the Core 30 (C30) and Breast cancer 23 (BR23) module of the European Organization for Research and Treatment Cancer Quality of Life Questionnaire (EORTC-QLQ), both of which have been validated for Koreans. Participants were asked about their adherence to dietary guidelines for breast cancer survivors, suggested by the Korean breast cancer society, using a 5-point Likert scale. We summed dietary guideline adherence scores for each participant and calculated the least squares means of health-related quality of life according to dietary guideline adherence scores using the generalized linear model. Results: Breast cancer survivors who had higher adherence to dietary guidelines for breast cancer survivors had lower constipation scores than those with lower adherence (p for trend=0.01). When we stratified by the stage at diagnosis, this association was limited to those who had been diagnosed with stage II or III breast cancers. Also, sexual functioning scores increased significantly with increasing adherence scores of dietary guidelines among those with stage II or III breast cancers (p for trend < 0.001). However, among those who had been diagnosed with stage I, higher scores of dietary guidelines were associated with higher scores of pain (p for trend=0.03) and breast symptoms (p for trend=0.05). Conclusions: Our study suggested that the health-related quality of life levels of breast cancer survivors are associated with the adherence to dietary guidelines and may differ by the stage of the breast cancer.

• Korean System Dynamics Review
• /
• v.1 no.2
• /
• pp.5-31
• /
• 2000

The summit meeting of the South North Korean leaders was a turning point in the relationships between the two countries. It was followed by the Red-Cross Meeting, Minister-Level Meeting, economic agreements, which have increased the relationship more colorful in both quantities and qualities. However, the half-century period for separation was too long to overcome all the problems by only one event. The two countries have quite different social systems; one politically strong person is governing the North, while many interest groups are involved in political decision making processes in the South. In short, it would take a long time to settle down all the problems residing between the two countries. A system dynamics model is developed to describe the long term dynamics of the relations between the South and North Koreas. As a first attempt, the model focuses only on the diplomatic meeting issues between the South and North. The model aggregates diplomatic issues into 5 categories; economic issues, security issues, infrastructure, cultural issues, and past problems. It assumes that there would not be any dramatic changes between the two countries. It is a conceptual model composed of around 200 variables, and should not be used as a forecast tool. However, it captures most of the logics discussed in the papers and conferences concerning the South and North Korea relations. Many sensitivity studies and Monte Carlo simulations have shown that the simulation results matches with mental models of experts; that is the model can be used as a learning tool or as a secondary opinion until the data required by the model is collected. In order to analyze the current situation, five scenarios are simulated and analyzed; the functional approach, the conditional approach, the balanced approach, the circumstantial approach, and the strategic approach. The functional approach represents that the South makes efforts in the area where the possibility of agreement is high for the next 10 years. The conditional approach is a scenario where the South impose all difficult issues as conditions for resolving other diplomatic issues. The balanced approach is resolving the five issues with the same priorities, while the circumstantial approach is resolving issues which seem to be resolved easily. Finally, another optimum approach has been seek using the system dynamics model developed. The optimum strategy (it is named as the strategic approach) was strikingly different from other four approaches. The optimum strategy is so complicated that no one could find it with mental model(or by just insights). Considering that the system dynamic model used to find the optimum is a simplifind (maybe over simplified) version of the reality, it is concluded that a well designed system dynamics model would be of great help to resolving the complicated diplomatic problems in any kind.

• Journal of Internet Computing and Services
• /
• v.21 no.5
• /
• pp.9-20
• /
• 2020

This study redefines the networks' connection behaviors and the terms confusion over the settlement in Netflix-SK Broadband's dispute through domestic and foreign legal references. Conflict parties, academics and the media use the terms "interconnection fee" or "Access fee" without uniformity, and in some cases mixes for strategic purposes. The use of different terms for the same phenomenon (or vice versa) has a high need for research in that it makes it difficult to reach a unified approach to the problem, to discuss it productively and rationally, and, moreover, to resolve disputes. Therefore, this study cross-referenced/analyzed terms related to network utilization and connectivity, namely "Use", "Access", "Interconnection" and thus cost-related terms as a counter-pay. In addition, it suggests that interconnection fees and access fees should be used separately, and allows them to function as a starting point in resolving future ICT sector issues. As a result of this study, the price against the network access/use between Netflix and SK Broadband is access fee or retail price, and proposes to be used uniformly in the term "interconnection fee" only for fees incurred in interconnection between ISPs that possess or operate networks.

• Atmosphere
• /
• v.30 no.2
• /
• pp.183-193
• /
• 2020

In this study, Yeongdong cold air damming (YCAD) cases that occur in winters have been selected using automatic weather station data of the Yeongdong region of Korea. The vertical and horizontal scales of YCAD were analyzed using rawinsonde and numerical weather model. YCAD occurred in two typical synoptic patterns such that low pressure and trough systems crossing and passing over Korea (low crossing type: LC and low passing type: LP). When the Siberian high does not expand enough to the Korean peninsula, low pressure and trough systems are likely to move over Korea. Eventually this could lead to surface temperature (3.1℃) higher during YCAD than the average in the winter season (1.6℃). The surface temperature during YCAD, however, was decrease by 1.3℃. The cold air layer was elevated around 120 m~450 m for LP-type. For LC-type, the cold layer were found at less than approximately 400 m and over 1,000 m, which could be thought of combined phenomena with synoptic and local weather forcing. The cross-sectional analysis results indicate the accumulation of cold air on the east mountain slope. Additionally, the north or northeasterly winds turned to the northwesterly wind near the coast in all cases. The horizontal wind turning point of LC-type was farther from the top of the mountain (52.2 km~71.5 km) than that of LP-type (20.0 km~43.0 km).

• Korean Journal of Food Science and Technology
• /
• v.35 no.5
• /
• pp.914-917
• /
• 2003

This study was undertaken to find the optimum condition for the Maillard browning reaction of tagatose and glycine model solution by applying the response surface methodology. Independent variables were pH (3, 5, 7), temperature (70, 85, $100^{\circ}C$), and time (60, 180, 300 min), while the dependent variables were absorbance, yellowness, color difference, and organoleptic score. The quadratic models with the cross-product proved to be suitable, due to the high coefficients of determination and the lack of fit results. Since all the dependent variables had saddle points, the optimal points were determined through ridge analysis. For absorbance, yellowness, and color difference, the optimal points were the lowest values; in contrast, the optimal point of organoleptic score was the highest value.

• Journal of the Korean GEO-environmental Society
• /
• v.7 no.6
• /
• pp.101-111
• /
• 2006

In case of drilled shafts installed by drilling through soft overburden onto a strong rock, the piles can be regarded as end-bearing elements and their working load is determined by the safe working stress on the pile shaft at the point of minimum cross-section or by code of practice requirements. Drilled shafts drilled down for some depth into weak or weathered rocks and terminated within these rocks act partly as friction and partly as end-bearing piles. The base resistance component can contribute significantly to the ultimate capacity of the pile. However, the shaft resistance is typically mobilized at considerably smaller pile movements than that of the base. In addition, the base response can be adversely affected by any debris that is left in the bottom of the socket. The reliability of base response therefore depends on the use of a construction and inspection technique which leaves the socket free of debris. This may be difficult and costly to achieve, particularly in deep sockets, which are often drilled under water or drilling slurry. As a consequence of these factors, shaft resistance generally dominates pile performance at working loads. The efforts to improve the prediction of drilled shaft pile performance are therefore primarily concerned with the complex mechanisms of shaft resistance development. In this study, the numerical analyses are carried out to investigate the behavior characteristics of side of rock socketed drilled shafts varying the loading condition at the pile head. The difference of behavior characteristics of side resistance is also evaluated with the effects of modelling of asperity.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.16 no.1
• /
• pp.13-25
• /
• 2000

Optimal Pressable Ceramic is one of the all-ceramic restorations with a shaded translucent pressed core and layering porcelains. The purpose of this study was to evaluate the marginal fidelity according to margin types and measurement sites, and to evaluate fracture strength according to margin types. Twenty seven OPC crowns made according to 3 types of cervical finishing lines were used in this study. Marginal gaps were measured before and after cementation. A Steromicroscope(SZ-ST(R), Olympus, Japan) was used to measure the space between the margin of OPC crown and the finishing line of metal model. Marginal gaps were measured at the labial, mesial, lingual and distal site, which were demonstrated in advance. Fracture strength testing was carried out using an Instron(Model M100EC, Mecmesin, England) at a cross head speed of 5 mm/min. All crowns were loaded until catastrophic failures occurred. The result were as follow: 1. In comparison according to variable margin before cementation, the marginal gap were increased in chamfer margin($47.50{\pm}18.39{\mu}m$), $120^{\circ}$shoulder margin ($55.21{\pm}14.4{\mu}m$) and $90^{\circ}$shoulder margin($71.18{\pm}13.30{\mu}m$) in ascending order, and there were significant differences between chamfer margin and $90^{\circ}$shoulder margin, $120^{\circ}$shoulder margin and between $120^{\circ}$shoulder margin and $90^{\circ}$shoulder margin respectively(p<0.05). 2. In comparison according to variable margin after cementation, the gap discrepancies were increased in chamfer margin($60.78{\pm}30.37{\mu}m$), $120^{\circ}$shoulder margin($66.67{\pm}11.18{\mu}m$) and $90^{\circ}$shoulder margin($85.78{\pm}17.23{\mu}m$) in ascending order, but there was significant difference only between chamfer margin and $90^{\circ}$shoulder margin(p<0.05). 3. Labio-lingual points showed a better marginal fidelity than that of proximal point(p<0.05). 4. Chamfer margin($48.76{\pm}8.45kgf$) showed higher fracture strength than $120^{\circ}$ shoulder margin($40.57{\pm}7.90kgf$) and $90^{\circ}$ shoulder margin(32.7.90kgf) (p<0.05), but there was significant difference only between chamfer margin and $90^{\circ}$ shoulder margin(p<0.05).