• Title/Summary/Keyword: 2 order system

Search Result 14,811, Processing Time 0.05 seconds

A Study of brain Atlases in Hippocampus Volume Measurement Using IBASPM (IBASPM을 이용한 해마체적 측정에서 뇌 Atlases에 대한 고찰)

  • Kim, Ju-ho;Lee, Ju-won;Kim, Seong-hu
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2014.10a
    • /
    • pp.981-984
    • /
    • 2014
  • Volumetric measurement of hippocampus using IBASPM, the 20's normal adults 10 people's brain images were acquired in order to assess the changes according to the type of the Atlas. Images was obtained using MPRAGE of a 3-D gradient echo pulse sequence on Head matrix coil of 1.5T MRI system. The results of Paired t-test using obtained volume of hippocampus depending on the type of the Atlas, Atlas69-Altas84, Atlas69-Atlas116(p=0.729, 0.729) in the left hippocampus and Atlas69-Atlas84, Atlas69-Atlas116(p=0.219, 0.219) in right hippocampal formation were no significant differences but in the area except this, there was significant difference(p=0.000). The volume of the hippocampus using Atlas84 and Atlas116, represented the same value and there was no significant difference. In the image analysis using the overlay of atlas image and original image, Atlas71 could be found that the area of hippocampus did mismatch. In the case of atlas used in this study, because it has been developed by the westerners, there are differences between brain of asian. It would be needed to development of new Atlas for high accuracy measurement of the volume of hippocampus.

  • PDF

A Study on high efficiency Bridgeless PFC Converter applied SiC SBD (SiC SBD 적용한 고효율 Bridgeless PFC 컨버터에 대한 연구)

  • Jeon, Joon-Hyeok;Kim, Hyung-Sik;Kim, Hee-Jun;Ahn, Joon-Seon
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
    • /
    • v.12 no.4
    • /
    • pp.449-455
    • /
    • 2019
  • This paper proposes a flyback diode of bridgeless PFC converter as SiC SBD (Schottky Barrier Diode) to achieve high efficiency. In addition, through the explanation of the operation principle of the bridgeless PFC converter, the conduction section of the freewheel diode is shown in the bridgeless PFC converter to verify the contribution of system loss due to the loss of the freewheel diode. The advantages of the SiC SBD device's physical properties and the reverse recovery characteristics are explained, and the efficiency is measured by measuring the turn-on and turn-off losses. The loss was calculated. The simulation results were calculated in consideration of device characteristics and verified through the waveform analysis and comparison of the actual system. In order to consider the device characteristics, the simulation was conducted using the thermal module of PSIM. As a result of the prototype test, the turn-on loss was 0.608W and the turn-off loss was 21.62W, resulting in the total switching loss of 22.228W. The comparison of the two results proved the validity of the experimental method. In addition, a high efficiency of 94.58% is achieved.

Numerical Modelling of One Dimensional Gas Injection Experiment using Mechanical Damage Model: DECOVALEX-2019 Task A Stage 1A (역학손상모델을 이용한 1차원 기체 주입 시험 모델링: 국제공동연구 DECOVALEX-2019 Task A Stage 1A)

  • Lee, Jaewon;Lee, Changsoo;Kim, Geon Young
    • Tunnel and Underground Space
    • /
    • v.29 no.4
    • /
    • pp.262-279
    • /
    • 2019
  • In the engineering barriers of high-level radioactive waste disposal, gases could be generated through a number of processes. If the gas production rate exceeds the gas diffusion rate, the pressure of the gas increases and gases could migrate through the bentonite buffer. Because people and the environment can be exposed to radioactivity, it is very important to clarify gas migration in terms of long-term integrity of the engineered barrier system. In particular, it is necessary to identify the hydro-mechanical mechanism for the dilation flow, which is a very important gas flow phenomenon only in medium containing large amounts of clay materials such as bentonite buffer, and to develop and validate new numerical approach for the quantitative evaluation of the gas migration phenomenon. Therefore, in this study, we developed a two-phase flow model considering the mechanical damage model in order to simulate the gas migration in the engineered barrier system, and validated with 1D gas flow modelling through saturated bentonite under constant volume boundary conditions. As a result of numerical analysis, the rapid increase in pore water pressure, stress, and gas outflow could be simulated when the dilation flow was occurred.

A Study on Achievements and Challenges of 70 Years of the Korean Federation of Teachers' Association (한국교총 70년의 성과와 과제)

  • Shin, Hyun-Seok;Ju, Yeong-Hyo;LEE, IN SU;Kim, Sang-cheol
    • (The)Korea Educational Review
    • /
    • v.24 no.3
    • /
    • pp.137-166
    • /
    • 2018
  • The purpose of this study was to analyze and present the achievements and challenges of the 70th year of the Korean Federation of Teachers' Association (KFTA). The KFTA was founded in 1947 as the Chosun Education Association, and it was the 70th anniversary of its founding in 2017. Throughout its 70?year history, the KFTA, which has emphasized and promoted expertise and professionalism, has continued to improve the professionalism of the teaching profession through research, improve the socio?economic status of teachers, and expand the welfare system in order to improve the quality of teaching and teaching environment. In addition, the KFTA contributed to the development of national education by participating in educational policies to improve education system and educational environment, as well as activities as a professional organization, and has promoted international status through the promotion of international exchange. After analyzing the academic literature and KFTA related data diachronically, this research suggested achievements and challenges as three aspects: the status as teachers' professional organizations, the activities as interests and pressure groups, and the activities as professional organizations.

A Case Study on How to Develop a Competency-Based General Education Curriculum (H대학교 교양이수체계 개편 사례 연구)

  • Shin, Young-Hun
    • The Journal of the Korea Contents Association
    • /
    • v.21 no.2
    • /
    • pp.351-361
    • /
    • 2021
  • With the advent of the Fourth Industrial Revolution, the liberal arts education of universities has been called for fundamental innovation in its content and methods. H university has continuously made efforts to improve its general education curriculum with the goal of satisfying students' needs as well as the demands of the times. Its efforts can be summarized as the harmonization of competency-based education and the traditional liberal arts education. In more detail, it has tried to meet the demands of Ministry of Education which requests each university to establish its general education system focusing on key competencies. Simultaneously, it also radically changed its education system based on the guidelines of the Korea National Institute for General Education(KONIGE). The starting point of those changes was the basic consulting by KONIGE in 2017. According to the consulting report, H university introduced comprehensive and overall revision of its liberal arts education curriculum, increasing its liberal arts credit requirements from 22 to 28 credits in 2019. It has also reorganized and reclassified its liberal arts courses by introducing distributive elective classes. In 2020, in accordance with the guidelines of the Ministry of Education, H university altered its curriculum once more in order to establish a competency-based general education curriculum. Under the new curriculum, all requirement subjects are completely matched with key competencies of H university. It also includes newly opened courses and subject areas such as "Social Service" and "Global Citizenship." Through these changes, H university hopes that its general education contributes to fostering students equipped with key competencies, who can face actively this challenging period.

Research Trends on External Event Identification and Screening Methods for Safety Assessment of Nuclear Power Plant (원자력발전소 안전성 평가를 위한 외부사건 식별 및 선별 방법 연구동향)

  • Kim, Dongchang;Kwag, Shinyoung;Kim, Jitae;Eem, Seunghyun
    • Journal of the Society of Disaster Information
    • /
    • v.18 no.2
    • /
    • pp.252-260
    • /
    • 2022
  • Purpose: As the intensity and frequency of natural hazards are increasing due to climate change, external events that affecting nuclear power plants(NPPs) may increase. NPPs must be protected from external events such as natural hazards and human-induced hazards. External events that may occur in NPPs should be identified, and external events that may affect NPPs should be identified. This study introduces the methodology of identification and screening methods for external events by literature review. Method: The literature survey was conducted on the identification and screening methods of external events for probabilistic safety assessment of NPPs. In addition, the regulations on the identification and screening of external events were investigated. Result: In order to minimize the cost of external event impact analysis of nuclear power plants, research on identifying and screening external events is being conducted. In general, in the identification process, all events that can occur at the NPPs are identified. In the screening process, external events are selected based on qualitative and quantitative criteria in most studies. Conclusions: The process of identifying and screening external events affecting NPPs is becoming important. This paper, summarize on how to identify and screen external events for a probabilistic safety assessment of NPPs. It is judged that research on bounding analysis and conservative analysis methods performed in the quantitative screening process of external events is necessary.

Multimodal Route Selection from Korea to Europe Using Fuzzy AHP-TOPSIS Approaches: The Perspective of the China-Railway Express (한-유럽 복합운송 경로선택에 관한 연구 중국-유럽 화물열차를 중심으로)

  • Wang, Guan;Ahn, Seung-Bum
    • Journal of Korea Port Economic Association
    • /
    • v.37 no.4
    • /
    • pp.13-31
    • /
    • 2021
  • Since the signing of the Korea-Europe Free Trade Agreement, the volume of trade transactions between South Korea and Europe has increased. The traditional single-mode transport system has been transformed into an intermodal transport system using two or more modes of transport. In addition, the conventional sea and air transport routes have been restricted, leading to a decline in Korean exports to Europe, and the rail transport mode is becoming mainstream in the market due to the influence of COVID-19. This paper focuses on the China-Railway Express to explore a new intermodal transport route from Korea to Europe. First, the fuzzy analytic hierarchy process (AHP) is used to evaluate the factor weights when selecting intermodal transport routes from Korea to Europe. Then, the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method is used to rank three alternatives. The results show that among the four factors (total cost, total time, transportation capability, and service reliability), the total cost is the most significant factor, followed by the total time, service reliability, and transportation capability. Furthermore, the alternative route 1 (Incheon-Dalian-Manchuria-Hamburg) is preferred.

A study on the honeycomb entry and exit counting system for measuring the amount of movement of honeybees inside the beehive (벌통 내부 꿀벌 이동량 측정을 위한 벌집 입·출입 계수 시스템 연구)

  • Kim, Joon Ho;Seo, Hee;Han, Wook;Chung, Wonki
    • The Journal of the Convergence on Culture Technology
    • /
    • v.7 no.4
    • /
    • pp.857-862
    • /
    • 2021
  • Recently, rapid climate change has had a significant impact on the bee ecosystem. The decrease in the number of bees and the change in the flowering period have a huge impact on the harvesting of beekeepers. Accordingly, attention is focused on smart beekeeping, which introduces IoT technology to beekeeping. According to the characteristics of beekeeping, it is impossible to continuously observe the beehive in the hive with the naked eye, and the condition of the hive is mostly dependent on knowledge from experience. Although a system that can measure partly through sensors such as temperature/humidity change inside the hive and measurement of the amount of CO2 is applied, there is no research on measuring the movement path and amount of movement of bees inside the beehive. Part of the migration of honeybees inside the hive can provide basic information to predict the most important cleavage time in beekeeping. In this study, we propose a device that detects the movement path of bees and measures and records data entering and exiting the hive in real time. The device proposed in this study was developed according to the honeycomb standard of the existing beehive so that beekeeping farms could use it. The development method used a photodetector that can detect the movement of bees to configure 16 movement paths and to detect the movement of bees in real time. If the measured honeybee movement status is utilized, the problem of directly observing the colony with the naked eye in order not to miss the swarming time can be solved.

A Study on the Establishment of Design and Construction Process Standardization through Building BIM Application Case (건축물 BIM 적용사례를 통한 설계 및 시공프로세스 표준화 수립에 대한 연구)

  • Jeong, Hee-woong
    • Journal of the Korea Institute of Building Construction
    • /
    • v.22 no.4
    • /
    • pp.347-358
    • /
    • 2022
  • In order to satisfy the extraction and use of information such as estimates and processes required in the design and construction stages of BIM, which is an expectation of overall construction operation for the design and construction stage of domestic buildings, it is insufficient to supply and apply mobile technologies or terminals. In this paper, standardization of BIM-based processes from the design stage to the construction stage is proposed as an efficient construction system method through mobile-based simulation and test-bed case analysis review. The current status and potential of BIM application were identified through theoretical review of BIM and case studies at home and abroad. In addition, the overall flow of the project and the direction of effective process construction were investigated through each process by 3D, 4D, and 5D execution stage and the role of each collaborator. 4D building process BIM simulation system using mobile was implemented by applying a visualization engine that simulates process information, object information connection module, and related object information. Therefore, it was possible to minimize the possibility of re-construction of the BIM design and construction process model through the visualization of 2D drawings based on the 3D model of the building and the review of errors and interferences in the drawings. In addition, in the implementation of simulation for each process of the construction process through mobile devices, it was possible to support construction progress and process management according to the optimal option selected by the user.

Damage Analysis of Manganese Crossings for Turnout System of Sleeper Floating Tracks on Urban Transit (도시철도 침목플로팅궤도 분기기 망간크로싱의 손상해석)

  • Choi, Jung-Youl;Yoon, Young-Sun;Ahn, Dae-Hee;Han, Jae-Min;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
    • /
    • v.8 no.5
    • /
    • pp.515-524
    • /
    • 2022
  • The turnout system of the sleeper floating tracks (STEDEF) on urban transit is a Anti-vibration track composed of a wooden sleeper embedded in a concrete bed and a sleeper resilience pad under the sleeper. Therefore, deterioration and changes in spring stiffness of the sleeper resilience pad could be cause changes in sleeper support conditions. The damage amount of manganese crossings that occurred during the current service period of about 21 years was investigated to be about 17% of the total amount of crossings, and it was analyzed that the damage amount increased after 15 years of use (accumulated passing tonnage of about 550 million tons). In this study, parameter analysis (wheel position, sleeper support condition, and dynamic wheel load) was performed using a three-dimensional numerical model that simulated real manganese crossing and wheel profile, to analyze the damage type and cause of manganese crossing that occurred in the actual field. As a result of this study, when the voided sleeper occurred in the sleeper around the nose, the stress generated in the crossing nose exceeded the yield strength according to the dynamic wheel load considering the design track impact factor. In addition, the analysis results were evaluated to be in good agreement with the location of damage that occurred in the actual field. Therefore, in order to minimize the damage of the manganese crossing, it is necessary to keep the sleeper support condition around the nose part constant. In addition, by considering the uniformity of the boundary conditions under the sleepers, it was analyzed that it would be advantageous to to replace the sleeper resilience pad together when replacing the damaged manganese crossing.