• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.30 no.4
• /
• pp.323-332
• /
• 2008

Aim of the study: Scaffolds are crucial to tissue engineering/regeneration. Biodegradable polymer/ceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. In this study, poly(L-lactide)/hydroxyapatite(PLLA/HA) composite scaffolds were fabricated for in vivo bone tissue engineering. Material & methods: In this study, PLLA/HA composite microspheres were prepared by double emulsion-solvent evaporation method, and were evaluated in vivo bone tissue engineering. Bone marrow mesenchymal stem cell from rat iliac crest was differentiated to osteoblast by adding osteogenic medium, and was mixed with PLLA/HA composite scaffold in fibrin gel and was injected immediately into rat cranial bone critical size defect(CSD:8mm in diameter). At 1. 2, 4, 8 weeks after implantation, histological analysis by H-E staining, histomorphometric analysis and radiolographic analysis were done. Results: BMP-2 loaded PLLA/HA composite scaffolds in fibrin gel delivered with osteoblasts differentiated from bone marrow mesenchymal stem cells showed rapid and much more bone regeneration in rat cranial bone defects than control group. Conclusion: This results suggest the feasibility and usefulness of this type of scaffold in bone tissue engineering.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.5
• /
• pp.593-600
• /
• 2014

In this paper, Radar cross section (RCS) calculations of advanced naval vessels model with RCS reduction methods are simulated and RCS results are discussed. Especially, this paper are mainly focusing on the facts influencing on RCS, the ways minimizing RCS and material characteristics of RCS changing-rate. RCS analysis results are given for a DDG-1000 type advanced naval vessels, which show that as the elevation angle increased 10 degree, the mean RCS value increased 23.91 dBsm. Also, as the superstructure angle increased 6 degree, the mean RCS value reduced 1.27 dBsm. Finally, the radar absorbing material attachment at the front and back superstructure have been reduced 2.27 dBsm in terms of mean RCS value.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.4
• /
• pp.641-647
• /
• 2018

Recently, CCTV, which provides video information for multiple purposes, has been transformed into an intelligent, and the range of automation applications increased using the computer vision. A highly reliable detection method must be performed for accurate recognition of pedestrians and vehicles and various methods are being studied for this purpose. In such an object detection system. In this paper, we propose a method to detect a large number of pedestrians by acquiring three characteristic information that features of color information using HSI, motion vector information and shaping information using HOG feature information of a pedestrian in a situation where a large number of pedestrians are moving. The proposed method distinguishes each pedestrian while minimizing the failure or confusion of pedestrian detection and tracking. Also when pedestrians approach or overlap, pedestrians are identified and detected using stored frame feature data.

• Restorative Dentistry and Endodontics
• /
• v.40 no.2
• /
• pp.123-127
• /
• 2015

Objectives: Glide path preparation is recommended to reduce torsional failure of nickel-titanium (NiTi) rotary instruments and to prevent root canal transportation. This study evaluated whether the repetitive insertions of G-files to the working length maintain the apical size as well as provide sufficient lumen as a glide path for subsequent instrumentation. Materials and Methods: The G-file system (Micro-Mega) composed of G1 and G2 files for glide path preparation was used with the J-shaped, simulated resin canals. After inserting a G1 file twice, a G2 file was inserted to the working length 1, 4, 7, or 10 times for four each experimental group, respectively (n = 10). Then the canals were cleaned by copious irrigation, and lubricated with a separating gel medium. Canal replicas were made using silicone impression material, and the diameter of the replicas was measured at working length (D0) and 1 mm level (D1) under a scanning electron microscope. Data was analysed by one-way ANOVA and post-hoc tests (p = 0.05). Results: The diameter at D0 level did not show any significant difference between the 1, 2, 4, and 10 times of repetitive pecking insertions of G2 files at working length. However, 10 times of pecking motion with G2 file resulted in significantly larger canal diameter at D1 (p < 0.05). Conclusions: Under the limitations of this study, the repetitive insertion of a G2 file up to 10 times at working length created an adequate lumen for subsequent apical shaping with other rotary files bigger than International Organization for Standardization (ISO) size 20, without apical transportation at D0 level.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.5
• /
• pp.805-810
• /
• 2006

Defects in the conventional casting process of silver jewelry can result in famished products of mediocre hardness. To overcome the shortcomings of conventional methods, we proposed new press forming process, which involves applying uniaxial pressure on casting 92.5%Ag-6.5%Cu-1%Zn ring elements and shaping with a lath. We investigated Vickers hardness, density, and microstructure evolution by changing the applied uniaxial pressure. We report that our newly proposed process can increase the hardness up to 2.3 times and decrease average grain size by 50%. Our method leads to drastic mechanical property enhancements, and is thus suitable for casting tension-style jewelry.

• The Journal of Korean Society for School & Community Health Education
• /
• v.12 no.2
• /
• pp.113-127
• /
• 2011

Background: University health services have provided comprehensive medical care, counseling, health promotion, and public health services to their students and several other local institutions. To their faculty and staff, university health care centers have served occupational health services and employee assistant program. Purpose: We performed this study to review the health promotion services on two kinds of health care center with different style of university formate. Methods: We tried to collect the data by literature review and interview with executive and provider at health care center in University of California at Berkeley and San Jose State University. Results: Our results were as followed. First, students could use the medical services just as they would their regular doctor's office and urgent care center. Second, the health promotion unit offered programs and services for keeping students healthy and safe, including many opportunities for students to get involved in shaping the public health of the campus. Third, the health promotion recommendation offered from ACHA was useful guideline to improve health status of their member in university campus. Finally, the student satisfaction surveys were used for evaluation and quality improvement. Conclusions: The systematic approach to improve health status of students, faculty and staff can use to maintain a state of optimum health among the diverse student community in support of academic excellence. Coupled with health promotion and public health programs, university health service have to reach all segments of the healthy campus community. To achieve study goals in university, the health care center contributes to promote accountability and responsibility for the health and well being of the members in their campus.

• Safety and Health at Work
• /
• v.7 no.1
• /
• pp.6-11
• /
• 2016

Background: A permit to work (PTW) is a formal written system to control certain types of work which are identified as potentially hazardous. However, human error in PTW processes can lead to an accident. Methods: This cross-sectional, descriptive study was conducted to estimate the probability of human errors in PTWprocesses in a chemical plant in Iran. In the first stage, through interviewing the personnel and studying the procedure in the plant, the PTW process was analyzed using the hierarchical task analysis technique. In doing so, PTWwas considered as a goal and detailed tasks to achieve the goal were analyzed. In the next step, the standardized plant analysis risk-human (SPAR-H) reliability analysis method was applied for estimation of human error probability. Results: The mean probability of human error in the PTW system was estimated to be 0.11. The highest probability of human error in the PTW process was related to flammable gas testing (50.7%). Conclusion: The SPAR-H method applied in this study could analyze and quantify the potential human errors and extract the required measures for reducing the error probabilities in PTW system. Some suggestions to reduce the likelihood of errors, especially in the field of modifying the performance shaping factors and dependencies among tasks are provided.

• Land and Housing Review
• /
• v.4 no.2
• /
• pp.177-184
• /
• 2013

This is a study regarding the efforts of the Gyong-gi Newtown Citizen Academy in Anyang Man-an Newtown and their role in shaping the urban design of their living environment. Our goal is to gauge how citizen participation may factor into the design process, from the early stages to the end result. The Newtown Academy diverged from the existing methods of a lecture centered approach to one that encouraged direct participation from the local citizens. We analyze the process and manner in which they drew up the plans. Our research focused on the winning proposal from the 2010 Citizen Academy Design competition, entitled 'Coexistence with Nature, Culture, History, Human - Eco-Cycle Man-an'. The Man-an team conducted regional analyses to come up with their own alternatives that would allow culture, leisure and nature to coexist in the space of their targeted area. The Newtown redevelopment promotion district reflected the actual implementation of the Man-an team's design. This study examines an urban design process in which citizens become directly involved, which presents the possibilities and directions of an urban design that is public and resident-oriented, in nature.

• The Journal of Advanced Prosthodontics
• /
• v.11 no.1
• /
• pp.48-54
• /
• 2019

PURPOSE. The aim of the present randomized controlled study was to compare prefabricated all-ceramic, anatomically shaped healing abutments followed by all-ceramic abutments and all-ceramic crowns and prefabricated standard-shaped (round-diameter) titanium healing abutments followed by final titanium abutments restored with porcelain-fused-to-metal (PFM) implant crowns in the premolar and molar regions. MATERIALS AND METHODS. Forty-two patients received single implants restored either by all-ceramic restorations (test group, healing abutment, final abutment, and crown all made of zirconia) or conventional titanium-based restorations. Immediately after prosthetic incorporation and after 12 months of loading, implant survival, technical complications, bone loss, sulcus fluid flow rate (SFFR) as well as plaque index (PI) and implant stability (Periotest) were analyzed clinically and radiologically. RESULTS. After 12 months of loading, an implant and prosthetic survival rate of 100% was observed. Minor prosthetic complications such as chipping of ceramic veneering occurred in both groups. No statistical significant differences were observed between both groups with only a minimum of bone loss, SFFR, and PI. CONCLUSION. All-ceramic implant prostheses including a prefabricated anatomically shaped healing abutment achieved comparable results to titanium-based restorations in the posterior region. However, observational results indicate a benefit as shaping the peri-implant soft-tissue with successive provisional devices and subsequent compression of the soft tissue can be avoided.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.34 no.3
• /
• pp.11-21
• /
• 2018

This paper explores the structure of space in architecture from a viewpoint that individual unitized spaces are gathered to form the whole. To understand the spatial structure of architecture, firstly we need to understand each unitized spaces, and secondly, one must understand how the following adjacent spaces are connected to form the whole building. this gives salience to a fact that understanding the whole comprehensively. It is the most fundamental bases that must be understood and unitized when understanding the spatial structure of an existing building and designing a new one. It is necessary to hypostatize space as an abstract notion. In regards to this space examines the logical flow of structure within actual space. Hypostasieren process includes the process of shaping space and the shape information. In this process we need to refer to the properties of space and the morphological characteristics of physical elements. The segment of the unitized space is the realization process of the basic space. This study aims to provide a theoretical basis for analysis and design of spatial structure by comparing several representative methods of segmenting unitized space.