• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.106-109
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• 2006

In this paper, the design and characteristics of a novel ultrasonic motor are investigated. Such a motor is appropriate far use in the optical zoom or auto focusing functions of the lens system in mobile phones. Its design and simulation of performances are carried out by FEM commercial software (ATILA). The shape of the motor is similar to a square without one side, on which an optical lens can be mounted. Two sheets of piezoelectric ceramics are adhered to both sides of two legs of the elastic body, respectively To drive the ultrasonic motor, the voltage is applied to two sheets of piezoelectric ceramics bonded to one leg. The rotation direction can be easily changed by switching the piezoelectric sheets bonded to the other leg, to which voltage is applied. A proto type of the motor is fabricated and its outer size is $10^*10^*2[mm3]$ including the camera lens of which the diameter is 7.5(mm). Its power consumption is about 0.3[W] and the speed of rotation is adjustable from 10 to 200[rpm] according to the applied voltage

• Geomechanics and Engineering
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• v.28 no.5
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• pp.521-529
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• 2022

This research work deals with the development of air pluviation method for preparing uniform sand specimens for conducting large scale laboratory testing. Simulating real field conditions and to get reliable results, air pluviation method is highly desirable. This paper presents a special technique called air pluviation or sand raining technique for achieving uniform relative density. The apparatus is accompanied by a hopper, shutters with different orifice sizes and numbers and set of sieves. Before using this apparatus, calibration curves are drawn for relative density against different height of fall (H) and shutter sizes. From these calibration curves, corresponding to the desired relative density of 60%, the shutter size of 13mm and height of fall of 457.2 mm, are selected and maintained throughout the pluviation process. The density obtained from the mobile pluviator is then verified using the Dynamic Cone Penetrometer (DCP) test where the soil is poured in the box using defined shutter size and fall height. The results obtained from the DCP test are averaged as 60±0.5 which was desirable. The mobile pluviator used in this research is also capable of obtaining relative densities up to 90%. The instrument is validated using experimental and numerical approach. In numerical study, Plaxis 3D software is used in which the soil mass is defined by 10-Node tetrahedral elements and 6-Node plate is used to simulate plate behavior in the validation phase. The results obtained from numerical approach were compared with that of experimental one which showed very close correlation.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.123-125
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• 2012

임베디드 소프트웨어에서의 테스팅은 하드웨어에 의존도가 높기 때문에 일반적인 소프트웨어에서의 테스팅과 달리 다양한 테스트 기법과 도구를 활용한 기술 집약적 테스트가 미약하고, 다른 펌웨어에서 테스팅 할 경우 테스팅이 제대로 되지 않는다. 본 논문에서는 하드웨어 의존도가 높은 임베디드 소프트웨어의 모듈을 펌웨어가 다른 x86의 환경에서 테스팅 할 수 있도록, 레지스터, 포트 등을 참조하는 부분을 로그로 출력하고, 모듈끼리의 의존성이 없도록 소스 코드를 수정하여, 공개 소스 테스팅 도구를 활용하여 단위 테스트 할 수 있도록 하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.143-146
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• 2007

테스트 주도 개발(TDD)에서는 무엇보다 테스팅의 중요성이 강조되고 있으며, 효율적인 단위 테스트를 통해 소프트웨어를 신속하게 개발할 수 있도록 자동화된 테스트 프레임워크를 지원한다. 본 논문은 소프트웨어를 개발하는 과정에서 소프트웨어의 기능뿐만 아니라 비기능적인 요소(non-functional factor)인 성능도 함께 고려하여 모바일 응용 소프트웨어를 개발하도록 하는 성능 테스트 방안을 제안한다. 본 논문에서는 모바일 응용 소프트웨어 성능 테스트 현황과 이슈를 살펴보고, 모바일 응용 소프트웨어 성능 테스트를 위해 필요한 성능 특성들을 분석하여, 테스트 주도 개발의 특징을 반영한 성능 테스트 방안에 대해 제시하고자 한다.

• Journal of the Korea Convergence Society
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• v.13 no.5
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• pp.229-236
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• 2022

The goal of this research is to understand the extent to which active seniors' mobile app usage level affects their lifestyle and life satisfaction. For this, we surveyed for 15 days in early December 2021 targeting about 150 users nationwide. As the questionnaire content, the independent variable was "mobile app usage level", the parameter was "lifestyle", and the dependent variable was "life satisfaction". As a result of empirical analysis, reliability and exploratory factors between each variable were verified, and it was confirmed that internal consistency was secured. It was investigated that the concentration validity of each item was generally well confirmed. As a result of hypothesis testing by the structural equation, 'App usage level ⇨ Lifestyle' was 0.244, 'Lifestyle ⇨ Life satisfaction' 0.707, and 'App usage level ⇨ Life satisfaction 0.141' was adopted. This study shows that the higher the level of mobile app usage of active seniors, the higher the lifestyle. Also, the better the lifestyle, the better the quality of life. It is analyzed that life satisfaction will improve as the level of mobile app use increases. Therefore, in order to improve life satisfaction, it seems necessary to increase the level of app use and lifestyle.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.241-245
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• 2006

In this paper, the design and characteristics of a $\pi-shaped$ ultrasonic motor that is applicable to optical zoom operation of a lens system for mobile phones are investigated. Its design and simulation of performances are carried out by FEM (finite element method) commercial software. As a simulation result, by applying voltage with single phase, a combined vibration is produced at the surface of a stator arm. A prototype of the motor is fabricated and its outer size is $8*4*2mm^3$ including the cylindrical steel rod of 2 mm in diameter as the rotor. The motor exhibits a maximum speed of 500 rpm and a power consumption of 0.3 W when driven at 20 Vpp and 64 kHz.

• The KIPS Transactions:PartA
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• v.11A no.3
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• pp.109-114
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• 2004

Increasing popularity of WLAN and advancement of WPAN allow user to connect to the Internet easily today. The increasing of number of networking mobile device such as laptop and PDA requires computing devices to share high speed Internet line or work on networks in most cases. This has stimulated the demand of access point that supports multiple network interfaces. This paper describes the process of design, implementation and test of the wired/wireless integrated access point that supports multiple network interfaces such as wired LAN, wireless LAN, Bluetooth, and Broadband network. We designed and developed the hardware system and protocol software to integrate heterogeneous network. The system has shown compatibility with standard specification and good performance through testing with various network devices.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1167-1175
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• 2021

The process of automation and monitoring in industrial control system involves the use of many types of sensors. A programmable logic controller plays an important role in the automation of the different processes in the power plant system. The major control units are boiler for temperature and pressure, turbine for speed of motor, generator for voltage, conveyer belt for fuel. The power plant units are controlled using microcontrollers and PLCs, but FPGA can be the feasible solution. The paper focused on the design and simulation of hardware chip to monitor boiler, turbine, generator and conveyer belt. The hardware chip of the plant is designed in Xilinx Vivado Simulator 17.4 software using VHDL programming. The methodology includes VHDL code design, simulation, verification and testing on Virtex-5 FPGA hardware. The system has four independent buzzers used to indicate the status of the boiler, generator, turbine motor and conveyer belt in on/off conditions respectively. The GSM is used to display corresponding message on the mobile to know the status of the device in on/off condition. The system is very much helpful for the industries working on plant automation with FPGA hardware integration.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.345-357
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• 2023

This research investigates the relationship between the information quality, service quality, and system quality of lodging apps and the users' expectations, level of satisfaction, and intent to continue using them. For this objective, 418 respondents participated in a survey. To evaluate the hypotheses, the collected data were examined using SPSS 22.0 and AMOS 22.0 statistical software. This study constructed a model using information quality, service quality, system quality, expectancy, satisfaction, and intention to continue using the pre- and post-use relationship of users of accommodation applications. The results of testing the hypotheses indicated that system quality had no significant effect on expectancy, system quality and service quality had no significant effect on satisfaction, and all other hypotheses had significant effects. The conclusion of this research is that the app's system quality, including access speed, access barriers, and privacy, does not satisfy pre- and post-use expectations. In addition, the system quality and service quality of the application have little effect on the app's satisfaction. The information quality of the application has a considerable impact on expectation confirmation and satisfaction, expectation confirmation has an impact on satisfaction, and expectation confirmation and satisfaction have an impact on intention to continue using.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.179-186
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• 2012

Nowadays, the multihomed host equipped with multiple network interfaces has been interested research in next generation wireless network, because the mobile users expect that they can be able to access services not only anywhere, at any time and from any network but also simultaneously. This paper addresses the mobility simulation model of the multihomed node for supporting MIPv4 and MIPv6 function in an interworking of Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11 WLAN. The multihomed node with two air interfaces has been developed based on WiMAX and WLAN workstation node model in simulation software. The main point of the developed model is to support both MIPv4 and MIPv6 function, and provide network selection policy for the multihomed node between WiMAX and WLAN network. Based on the received Router Advertisement along with the interface number, we can manage the access interfaces in ordered list to make handover decision while the multihomed node is moving. In the end of this paper, the simulation scenarios and results are shown for testing MIPv4 and MIPv6 function.