• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.94-94
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• 2008

We have performed simulation for Junction Field Effect Transistor(JFET) using Silvco to improve its electrical properties. The device structure and process conditions of Si-control JFET(Si-JFET) were determined to set its cut off voltage and drain current(at Vg=0V) to -0.5V and $300{\mu}A$, respectively. From electrical property obtained at various implantation energy, dose, and drive-in conditions of p-gate doping, we found that the drive in time of p-type gate was the most determinant factor due to severe diffusion. Therefore we newly designed SiGe-JFET, in which SiGe layer is to epitaxial layers placed above and underneath of the Si-channel. The presence of SiGe layer lessen the p-type dopants (Boron) into the n-type Si channel the phenomenon would be able to enhance the structural consistency of p-n-p junction. The influence of SiGe layer will be discussed in conjunction with boron diffusion and corresponding I-V characteristics in comparison with Si-control JFET.

• Journal of The Korean Association For Science Education
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• v.23 no.2
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• pp.176-188
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• 2003

Self-induction is an important concept in the field of electromagnetism, which is dealt with in all the high school physics textbooks. According to the results of the survey on self-induction, most of general high school students and even science high school students have overgeneralized concepts that high self-induced emf. are produced whenever the switch is turned off in the circuit containing inductors. The reasons of this overgeneralization on self-induction could be explained through the analysis of current high school physics II textbooks. Main reasons can be attributed to the fact that, by depending on their intuitive ideas, students try to vaguely explain the concept, based on lighting up of Ne tube in the special circuit. This study found out qualitative method to have students effectively understand self-induction based on quantitative interpretation to gain scientific understanding on self-induction.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.425-437
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• 2016

Objective:The objective of this study is to develop an ergonomic toilet system along with constituent facilities that can be used with the front-entry sitting method when transferring from wheelchair to the toilet stool, instead of using the back-entry sitting method which is currently used. This system can offer more ease, convenience and safety for wheelchair users when using the restroom. Background: For users with disabilities, even a dedicated handicapped toilet requires maneuvering, especially when in a wheelchair. To transfer from wheelchair to the current back-entry sitting toilet, users need to get closer to the toilet and then turn or twist after erecting their body to get onto the toilet. This method induces inconvenience as well as secondary injury by falling when transferring to/from toilet. Method: To design a front-entry sitting toilet system, an ergonomics approach was applied which introduces a new design concept for people using wheelchairs. Using this toilet system, the wheelchair users don't need to turn or twist but can simply slide forward off the wheelchair directly onto the toilet stool in an easier and safer way. Results: The newly developed front-entry sitting toilet system is easier and safer for wheelchair users, and also space efficient requiring only two-thirds of the space of existing handicapped toilet. It is also usable by both individuals with disabilities and the general population. Conclusion: With the spread of the front-entry sitting toilet system developed in this study, wheelchair users can benefit from enhanced convenience and safety as well as significant restroom space savings. Additional effects can also be achieved such as improved self-esteem of people with disabilities by enabling to use the toilet on their own. Application: The newly developed front-entry sitting toilet system should enhance toilet accessibility to wheelchair users and the elderly. Introduction is needed with efforts at the national policy level and a macroscopic objective to promote the health and safety of the handicapped.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.983-988
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• 2016

Internet of Things Iranian people and things, things and things are connected through the Cloud. It can significantly save energy through a combination of LED lighting as a new ICT technologies and industry-to provide a human-centric, eco-friendly, and the content is embedded multifunction solutions that meet your needs, environment, implementation time according to user requirements, technology It can be systematized as converged next-generation lighting. In this paper, we have developed regarding whether the building in relation to the LED lighting control system using smart devices and Cloud-based user as a human connection through the board to the Arduino Yun lit LED lighting, wireless smart device or to the Cloud or off. After the Arduino Yun is connected to the Internet, taking the current date and time information from the Linux shell command used the way coming across the bridge (BRIDGE) its value.

• Journal of the Korean Society of Costume
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• v.64 no.5
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• pp.18-29
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• 2014

Modern male has displayed an increased desire to express their social influence and image, and the male fashion market has had to provide various styles and images to fill these needs. The current domestic menswear market, however, is unable to satisfy the needs of male consumers who have a need for diversity in a rapidly changing society; more segmented fashion images and styles are needed. The purposes of this study are to classify fashion images and to establish character of the types. This study was done by performing a literature review and a survey. This study proposed 10 categories of fashion style images. Men's fashion style is classified into the classic image, sophisticated image, urban casual image, chic modern image, mods modern image, basic casual image, ethnic image, avant-garde image, active & outdoor image, and street-kitsch image. In the case of the classic images, common in formal setting, men's formal wear is the main focus with the classic suit. The sophisticated image is that of a colorful formal wear seasoned with elegance. Urban casual image is contemporary image, and therefore is meant for city life wear. Chic and modern image conveys an urban image by seeking a simple and chic feel. Mods modern image is retro yet dandy, giving off a sense of youthfulness compared to the other classic images. Ethnic image expresses the exotic quality of folklore as the main representatives of the character casual wear. Avant garde image portrays strong character casual wear with oversized silhouettes or exaggerated details. Active & Outdoor image is leisure life wear conveying active, functional images. Street Kitsch image is men's street casual wear with graphic patterns such as pop art and graffiti. This study's significance lies in its presentation of fashion style data, which can be utilized in the design and marketing of fashion targeted to males.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.277-280
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• 2010

The prevention of disasters is important to prepare in advance through analysis and an estimate. But for all the efforts of the government to stave off disasters, the damage out of a guerilla localized heavy rain caused the global warming, a landslide and inundation is growing. To prevent these damages, the basic data and system through systematic research and analysis should be set up. But it is true that collecting of the basic data and the system for preventing disasters are either constructing or insufficient so far. In this research, by using topography spatial data including LiDAR data including the aerial photo and digital maps, and etc. the factor of a disaster, the disaster risk element was extracted. Moreover, the disaster region about the disaster generation available region was evaluated in advance using the easy disaster analysis of current situation photo map which made with the grid analysis method and weighted value estimate technique.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.347-357
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• 2017

The applications of active control is being more popular nowadays. Several control algorithms have been developed to determine optimum control force. In this paper, a Chaotic Particle Swarm Optimization (CPSO) technique, based on Logistic map, is used to compute the optimum control force of active tendon system. A chaotic exploration is used to search the solution space for optimum control force. The response control of Multi-Degree of Freedom (MDOF) shear buildings, equipped with active tendons, is introduced as an optimization problem, based on Instantaneous Optimal Active Control algorithm. Three MDOFs are simulated in this paper. Two examples out of three, which have been previously controlled using Lattice type Probabilistic Neural Network (LPNN) and Block Pulse Functions (BPFs), are taken from prior works in order to compare the efficiency of the current method. In the present study, a maximum allowable value of control force is added to the original problem. Later, a twenty-story shear building, as the third and more realistic example, is considered and controlled. Besides, the required Central Processing Unit (CPU) time of CPSO control algorithm is investigated. Although the CPU time of LPNN and BPFs methods of prior works is not available, the results show that a full state measurement is necessary, especially when there are more than three control devices. The results show that CPSO algorithm has a good performance, especially in the presence of the cut-off limit of tendon force; therefore, can widely be used in the field of optimum active control of actual buildings.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.239-244
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• 2013

This paper presents a design of the CMOS LDO regulator with a UVLO protection function for a high speed PMIC. Proposed LDO regulator circuit consists of a BGR reference circuit, an error amplifier and a power transistor and so on. UVLO block between the power transistor and the power supply is added for a low input protection function. Also, UVLO block showed normal operation with turn-off voltage of 2.7V and turn-on voltage of 4 V in condition of 5 V power supply. Proposed circuit generated fixed 3.3 V from a supply of 5V. From SPICE simulation results using a $1{\mu}m$ high voltage CMOS technology, simulation results were 5.88 mV/V line regulation and 27.5 uV/mA load regulation with load current 0 mA to 200 mA.

• Journal of IKEEE
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• v.17 no.3
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• pp.284-293
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• 2013

This paper describes a DC-DC boost converter for thermoelectric energy harvesting. The designed converter boosts the VDD through a start-up block from a low-output voltage of a thermoelectric device and the boosted VDD is used to operate the internal control block. When the VDD reaches a predefined value, a detector circuit makes the start-up block turn off to minimize current consumption. The final boosted VOUT is achieved by alternately operating the DC-DC converter for VDD and the main DC-DC converter for VOUT according to the comparator outputs. Simulation results shows that the designed converter generates 2.65V from an input voltage of 200mV and its maximum power efficiency is 63%. The area of the chip designed using a 0.35um CMOS process is $1.3mm{\times}0.7mm$ including pads.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2505-2511
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• 2014

Indium oxide nanocrystals ($In_2O_3$ NCs) with sizes of 5.5 nm-10 nm were synthesized by hot injection of the mixture precursors, indium acetate and oleic acid, into alcohol solution (1-octadecanol and 1-octadecence mixture). Field emission transmission electron microscopy (FE-TEM), High resolution X-Ray diffraction (X-ray), Nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FT-IR) were employed to investigate the size, surface molecular structure, and crystallinity of the synthesized $In_2O_3$ NCs. When covered by oleic acid as a capping group, the $In_2O_3$ NCs had a high crystallinity with a cubic structure, demonstrating a narrow size distribution. A high mobility of $2.51cm^2/V{\cdot}s$ and an on/off current ratio of about $1.0{\times}10^3$ were observed with an $In_2O_3$ NCs thin film transistor (TFT) device, where the channel layer of $In_2O_3$ NCs thin films were formed by a solution process of spin coating, cured at a relatively low temperature, $350^{\circ}C$. A size-dependent, non-monotonic trend on electron mobility was distinctly observed: the electron mobility increased from $0.43cm^2/V{\cdot}s$ for NCs with a 5.5 nm diameter to $2.51cm^2/V{\cdot}s$ for NCs with a diameter of 7.1 nm, and then decreased for NCs larger than 7.1 nm. This phenomenon is clearly explained by the combination of a smaller number of hops, a decrease in charging energy, and a decrease in electronic coupling with the increasing NC size, where the crossover diameter is estimated to be 7.1 nm. The decrease in electronic coupling proved to be the decisive factor giving rise to the decrease in the mobility associated with increasing size in the larger NCs above the crossover diameter.