• Journal of Power Electronics
• /
• v.16 no.1
• /
• pp.362-373
• /
• 2016

The on-line measurement of high-power IGBT collector current is important for the hierarchical control and short-circuit and overcurrent protection of its driver and the sensorless control of the converter. The conventional on-line measurement methods for IGBT collector current are not suitable for engineering measurement due to their large-size, high-cost, low-efficiency sensors, current transformers or dividers, etc. Based on the gate driver, this paper has proposed a current measuring circuit for IGBT collector current. The circuit is used to conduct non-intervention on-line measurement of IGBT collector current by detecting the voltage drop of the IGBT power emitter and the auxiliary emitter terminals. A theoretical analysis verifies the feasibility of this circuit. The circuit adopts an operational amplifier for impedance isolation to prevent the measuring circuit from affecting the dynamic performance of the IGBT. Due to using the scheme for integration first and amplification afterwards, the difficult problem of achieving high accuracy in the transient-state and on-state measurement of the voltage between the terminals of IGBT power emitter and the auxiliary emitter (u_Ee) has been solved. This is impossible for a conventional detector. On this basis, the adoption of a two-stage operational amplifier can better meet the requirements of high bandwidth measurement under the conditions of a small signal with a large gain. Finally, various experiments have been carried out under the conditions of several typical loads (resistance-inductance load, resistance load and inductance load), different IGBT junction temperatures, soft short-circuits and hard short-circuits for the on-line measurement of IGBT collector current. This is aided by the capacitor voltage which is the integration result of the voltage uEe. The results show that the proposed method of measuring IGBT collector current is feasible and effective.

• The KIPS Transactions:PartB
• /
• v.10B no.1
• /
• pp.1-12
• /
• 2003

In this paper, we Introduce the Unreal Tournament (UT) game and the Gamebots system. The former it a well-known 3D first-person action game and the latter is an intelligent agent research testbed based on UT And then we explain the design and implementation of KGBot, which is an intelligent non-player character deploying effectively within the 3D virtual environment provided by UT and the Gamebots system. KGBot is a bot client within the Gamebots System. KGBot accomplishes its own task to find out and dominate several domination points pro-located on the complex surface map of 3D virtual environment KGBot adopts UM-PRS as its control engine, which is a general BDI agent architecture. KGBot contains a hierarchical knowledge base representing its complex behaviors in multiple layers. In this paper, we explain details of KGBot's Intelligent behaviors, tuck af locating the hidden domination points by exploring the unknown world effectively. constructing a path map by collecting the waypoints and paths distributed over the world, and finding an optimal path to certain destination based on this path graph. Finally we analyze the performance of KGBot exploring strategy and control engine through some experiments on different 3D maps.

• Animal Systematics, Evolution and Diversity
• /
• v.25 no.3
• /
• pp.325-329
• /
• 2009

Lepomis macrochirus from the family Centrarchidae, commonly known as Bluegill sunfish, is an introduced freshwater fish in Korea that thrives in lakes, ponds, reservoirs and rivers. Since its introduction into Korea in 1969, Lepomis macrochirus has rapidly dispersed out and increased in number almost all over the freshwater ecosystems in Korea. Consequently this species causes a severe ecological problem, threatening native fishes due to its omnivorous foraging behaviors upon fish juveniles and many freshwater invertebrates. To address population genetic structure of L. macrochirus, 74 fish samples from 10 populations were collected and compared for their mitochondrial D-loop control region. As the result we found that the genetic diversity of L. macrochirus is extremely low such as resulting only four haplotypes with a few nucleotide differences among them. Analysis of molecular variance (AMOVA) revealed that the source of population genetic variation is largely retained in the comparisons among individuals within populations, while it is relatively low with slight significance at the highest hierarchical group. This distribution pattern differs from what is expected when biogeography is under the influence of natural geographic barriers such as mountain ranges in Korea. Instead the result is accord with the influential role of random spreading events facilitated by local people for aquaculture and fishing, and subsequent dispersals since its single point of introduction into Korea.

• Journal of Preventive Medicine and Public Health
• /
• v.30 no.3 s.58
• /
• pp.540-554
• /
• 1997

The effects of cigarette smoking on the psychosocial distress, the absenteeism, the occupational injuries, and on the prevalence for the accidents were assessed in 795 male workers who had been employed since March 1994. The results show that the prevalence of current smokers were higher in young men, lower educational level, lower income, single men(unmarried or divorced), alcohol drinkers, and blue collar workers. In the bivariate analyses, the workers with the high job demand and low work control were more likely to smoke, although the relationship was not strong. Those who reported lower satisfaction on his job tended to smoke more. Mean scores of psychosocial well-being index(PWI) were higher in current smokers than nonsmokers. For the hierarchical multiple regression analyses, interaction terms between cigarette smoking and job stressors(job demand and work control) were not significant. For smokers, the odds ratios for the occupational injuries, and the accidents were 1.40(95% confidence interval 0.77-2.57) and 1.96 (95% confidence interval 0.75-5.09), respectively. The mean absent day were 4.13 for smokers, 3.65 for nonsmokers, although the differences were not statistically significant. It seems that cigarette smoking had not caused any crucial effects on the psychosocial well-being status and the occupational risks. Some considerations for the further research on the relationship of cigarette smoking on the mental health status and the occupational risks were also discussed.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.16 no.5
• /
• pp.544-549
• /
• 2006

This research is to introduce about Judgment System for Intelligent Movement(JSIM) that can perform assistance work of human brain. JSIM can order autonomous command and also it can be directly controlled by user. This research assumes that control object is limited to Mobile Robot(MR) Mobile robot offers image and ultrasonic sensor information to user carrying JSIM and it performs guide to user. JSIM having PDA and Sensor-box controls velocity and direction of the mobile robot by soft-computing method that inputs user's command and information that is obtained to mobile robot. Also it controls mobile robot to achieve various movement. This paper introduces wearable JSIM that communicates with around devices and that can do intelligent judgment. To verify the possibility of the proposed system, in real environment, the simulation of control and application problem lot mobile robot will be introduced. Intelligent algorithm in the proposed system is generated by mixed hierarchical fuzzy and neural network.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.687-694
• /
• 2008

Given the daily tactical schedule, the purpose of the traffic management system is to develop operating plan that will achieve the stated schedule as best as possible. The operating plan has to be modified during the day because of occurring disturbance(e.g. delay, infrastructure breakdown, etc.) Conflict detection and resolution(CDRS) are aimed for adjusting the distorted schedule to tactical schedule. Our research separate CDRS into two hierarchy modules, line conflict control module and station conflict control module. We define the role of each modules and design the cooperative architecture. We suggest the conflict detection and resolution approach based on mathematical model. These results can be implemented as prototype modules.

• Journal of the Korea Convergence Society
• /
• v.10 no.8
• /
• pp.327-334
• /
• 2019

This study was conducted to understand the relationship between elementary students' beliefs supporting aggression, aggression and self-esteem. In addition, we aimed to provide basic data for controlling the aggression of children and developing effective coping strategies. This study population consisted of 184 elementary school students. Data were analyzed using SPSS 24.0 program. As a result, the aggression of elementary school students showed a significant positive correlation with beliefs supporting aggression(r=.39, p<.001) and a significant negative correlation with self-esteem(r=-.46, p<.001). In addition, Results of the hierarchical regression analysis revealed that self-esteem has the mediating effect on the relationship between beliefs supporting aggression and aggression(${\beta}=.26$, p<.001). In other words, the higher the beliefs supporting aggression, the higher the aggression, and self-esteem means to act as a mediating effect in the relationship between them. Therefore, when arranging an intervention plan to control the aggression of elementary school students, it is necessary to find strategies to control the beliefs spporting aggression and increase self-esteem.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.1
• /
• pp.39.1-39.1
• /
• 2021

The Local Volume Mapper(LVM) project in the fifth iteration of the Sloan Digital Sky Survey (SDSS-V) will produce large integral-field spectroscopic survey data to understand the physical conditions of the interstellar medium in the Milky Way, the Magellanic Clouds, and other local-volume galaxies. We are developing the LVM Instrument control software. The architecture design of the software follows a hierarchical structure in which the high-level software packages interact with the low-level and mid-level software and hardware components. We adopt the spiral software development model in which the software evolves by iteration of sequential processes, i.e., software requirement analysis, design, code generation, and testing. This spiral model ensures that even after being commissioned, the software can be revised according to new operational requirements. We designed the software by using the Unified Modeling Language, which can visualize functional interactions in structure diagrams. We plan to use the SDSS software framework CLU for the interaction between components, based on the RabbitMQ that implemented the Advanced Message Queuing Protocol (AMQP).

• International Journal of Computer Science & Network Security
• /
• v.24 no.8
• /
• pp.32-42
• /
• 2024

The Internet of Things (IoT) is set to transform patient care by enhancing data collection, analysis, and management through medical sensors and wearable devices. However, the convergence of IoT device vulnerabilities and the sensitivity of healthcare data raises significant data integrity and privacy concerns. In response, this research introduces the Smart-Coord system, a practical and affordable solution for securing healthcare IoT. Smart-Coord leverages blockchain technology and coordinate-based access management to fortify healthcare IoT. It employs IPFS for immutable data storage and intelligent Solidity Ethereum contracts for data integrity and confidentiality, creating a hierarchical, AES-CBC-secured data transmission protocol from IoT devices to blockchain repositories. Our technique uses a unique coordinate system to embed confidentiality and integrity regulations into a single access control model, dictating data access and transfer based on subject-object pairings in a coordinate plane. This dual enforcement technique governs and secures the flow of healthcare IoT information. With its implementation on the Matic network, the Smart-Coord system's computational efficiency and cost-effectiveness are unparalleled. Smart-Coord boasts significantly lower transaction costs and data operation processing times than other blockchain networks, making it a practical and affordable solution. Smart-Coord holds the promise of enhancing IoT-based healthcare system security by managing sensitive health data in a scalable, efficient, and secure manner. The Smart-Coord framework heralds a new era in healthcare IoT adoption, expertly managing data integrity, confidentiality, and accessibility to ensure a secure, reliable digital environment for patient data management.

• Journal of Broadcast Engineering
• /
• v.22 no.2
• /
• pp.193-206
• /
• 2017

In this paper, we propose a rate control method based on the $R-{\lambda}$ model that supports a parallel encoding structure in GOP levels or IDR period levels for 4K UHD input video in real-time. For this, a slice-level bit allocation method is proposed for parallel encoding instead of sequential encoding. When a rate control algorithm is applied in the GOP level or IDR period level parallelism, the information of how many bits are consumed cannot be shared among the frames belonging to a same frame level except the lowest frame level of the hierarchical B structure. Therefore, it is impossible to manage the bit budget with the existing bit allocation method. In order to solve this problem, we improve the bit allocation procedure of the conventional ones that allocate target bits sequentially according to the encoding order. That is, the proposed bit allocation strategy is to assign the target bits in GOPs first, then to distribute the assigned target bits from the lowest depth level to the highest depth level of the HEVC hierarchical B structure within each GOP. In addition, we proposed a processing method that is used to improve subjective image qualities by allocating the bits according to the coding complexities of the frames. Experimental results show that the proposed bit allocation method works well for frame-level parallel HEVC software encoders and it is confirmed that the performance of our rate controller can be improved with a more elaborate bit allocation strategy by using the preprocessing results.