• Transactions on Electrical and Electronic Materials
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• 제9권5호
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• pp.181-185
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• 2008

Using the extensional vibration mode of PZT ring, a piezopump is successfully made. The PZT ring is polarized with thickness direction. The traveling extensional wave along the circumference of the ring is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic ring. The pump takes an unobtrusive operation into the simple displacing mechanism using peristaltic traveling waves without the physical moving parts. The finite elements analysis on the proposed pump model is carried out to verify its operation principle and design by the commercial FEM software. Components of piezopump were made, assembled, and tested to validate the concepts of the proposed pump and confirm the simulation results. The performance of the proposed piezopump is about 580 ${\mu}l/min$ in flow rate with the highest pressure level of 0.85 kPa, when the driving voltage is 150 $V_p$, 57 kHz.

• 한국ITS학회 논문지
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• 제14권1호
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• pp.68-76
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• 2015

본 논문에서는 원형 배열 안테나를 장착한 차량이 이동하면서 메쉬 네트워크 환경을 구성할 때 다중 노드 빔 형성을 위한 안테나 선택 방식과 전력 제어 알고리즘을 제안한다. 제안한 안테나 선택 방법은 안테나의 방사 이득을 고려하여 빔 형성을 위한 안테나를 선택하고, 두 개 이상의 노드가 인접할 경우 배열 이득을 최대화하기 위해 안테나를 중복으로 선택한다. 제안한 전력 제어 알고리즘은 중복 안테나 선택 시 SIR이 최대가 되도록 각 안테나의 전력을 제어한다. 전산모의 실험을 통하여 제안한 알고리즘을 적용하여 기존의 방식과 비교하여 두 노드가 $15^{\circ}$로 인접했을 때 최대 2.5 dB의 SIR 향상을 보인다.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.547-553
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• 2021

Dynamic object recognition is an important task for autonomous vehicles. Since dynamic objects exhibit a higher collision risk than static objects, our own trajectories should be planned to match the future state of moving elements in the scene. Time information such as optical flow can be used to recognize movement. Existing optical flow calculations are based only on camera sensors and are prone to misunderstanding in low light conditions. In this regard, to improve recognition performance in low-light environments, we applied a normalization filter and a correction function for Gamma Value to the input images. The low light quality improvement algorithm can be applied to confirm the more accurate detection of Object's Bounding Box for the vehicle. It was confirmed that there is an important in object recognition through image prepocessing and deep learning using YOLO.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.71-80
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• 2018

The path and visibility of nurses in general hospital wards have been treated as architectural planning factors. However, the analysis approach of existing studies shows limitations that only fixed physical elements are considered without considering the behavior of users using space. Consider factors for analysis of ward and models based on this study model. Select a case hospital to apply the analysis technique and conduct the nurse questionnaire and route survey of the hospital. Establish a framework for analysis model applied with the path of nurse movements. The analysis model applies to the case hospital. The analysis results are aggregated to derive design suggestion for reference to the spatial improvement of the ward. Visible visibility to observe the bedside in the nursing station, visibility to observe the beds in the nurse's path, and visibility to observe patients moving in the nurse's path were derived from visual access frequency and exposure frequency. The survey of nurses' movements at the site allowed the nurses to calculate the distance required to move. Reflecting the path of nurse movement, a model was presented for a comprehensive analysis of nursing distance and nursing visibility, which could lead to improvement in the observation and visibility of nurses and the layout of patient rooms or day rooms.

• 대한건축학회논문집:계획계
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• 제36권1호
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• pp.37-48
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• 2020

Logistics centers, distribution centers, or warehouse facilities increasingly dominate urban and suburban landscapes, their enormous but blank, repetitive facades completely overshadowing adjacent buildings. Mostly ignored by architects, this new building type symbolically represents the arrival of post-anthropocene, or post-urbicene era of architecture, in which an increasing portion of our built environment will not be intended for human occupancy, but rather for use by machines and artificial intelligence. As a new wave of logistics centers are becoming more automated, and more supersized, it is important to deepen architects' understanding of the organizational logic and programming factors that inform the overall design decisions for these facilities. With a particular focus on three case studies--Coupang, E-Mart, and Amazon Fulfillment Centers, this research examines the current trends in automation and expansion of logistics centers, and offers an analysis and forecast for future facilities in South Korea.

• 대한건축학회논문집:계획계
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• 제35권12호
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• pp.21-29
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• 2019

The purpose of the study is to be the pedestrian integrated circulation system of malling route and the third route in Mixed-use Building based on User Behavior. The study has performed by the following approaches: Initially, literature reviews are performed related to a pedestrian route by user in mixed-use building. Second, general and stroller users moving route are analyzed based on the outcome of the case study. Finally, the study develops the efficient pedestrian integrated circulation system of malling route and the third route in Mixed-use Building. According to the study, the following conclusions were made: First, An integrated plan for escalators and EVs, which are accessible to both users and strollers, is needed. Second, The entrance automatic door and circulation elements should be connected for continuous move by the stroller users. Finally, The circulation system of complex buildings should be a simple spatial structure and route plan that users can easily recognize.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.43-54
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• 2021

The study evaluates India's technological advancement, which has created a range of opportunities for consumers to enter into digital payment space. Demonetization in India has forced all consumers and companies to embrace and create cashless digital payment platforms. The cashless economy scenario involves various factors for its adoption such as reach, availability and awareness. This study considers factors responsible for adopting new digital payment technologies in India's different regions across various consumers. The study includes descriptive statistics and variance analysis (ANOVA) to identify elements to achieve maximum satisfaction. The research collects data from 250 respondents living in India, experiencing digital payments and online transactions. The data is collected through a structured questionnaire and critically analyzed using statistical analysis. The data has been analyzed with no sectorial biases and tracked by creating real-time indications. The study uses various hypotheses after taking responses from a sample of respondents. Cronbach's Alpha analysis is also used to determine the validity and reliability of the data. The study illustrates the complete shift of consumer behavior from cash to a cashless economy. A certain number of factors are shown to directly influence the rate of such a shift toward digital transactions in India.

• Current Optics and Photonics
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• 제5권1호
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• pp.8-15
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• 2021

An elliptical zone plate (EZP) array is important in off-axis optical systems because it provides two advantages. First, the residual beam and the main source are not focused in the same direction and second, the light from the observation plane is not reflected back towards the beam source. However, the fill factor of the previous EZP array was about 76% which was a little low. Hence, this EZP array could not collect the maximum amount of illumination light, which affected the overall optical performance of the lens array. In this study, we propose a new EZP array design with a 97.5% fill factor used in off-axis imaging system for enhancement of brightness and contrast. Then, direct laser lithography was used to fabricate the high fill factor EZP array by moving the XY linear stage of the system in a zigzag motion. The imaging properties of the proposed EZP array were experimentally verified at the focal plane and compared with the previous model.

• Current Optics and Photonics
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• 제7권3호
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• pp.273-282
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• 2023

This paper presents a new method for redistributing effectively the first orders of each lens element to achromatize and athermalize an optical system, by introducing a novel method for adjusting the slope of an achromatic and athermal line. This line is specified by connecting the housing, equivalent single lens, and aberration-corrected point on a glass map composed of available plastic and glass materials for molding. Thus, if a specific lens is replaced with the material characterized by the chromatic and thermal powers of an aberration-corrected point, we obtain an achromatic and athermal system. First, we identify two materials that yield the minimum and maximum slopes of the line from a housing coordinate, which specifies the slope range of the line spanning the available materials on a glass map. Next, redistributing the optical first orders (optical powers and paraxial ray heights) of lens elements by moving the achromatic and athermal line into the available slope range of materials yields a good achromatic and athermal design. Applying this concept to design a mobile-phone camera lens, we efficiently obtain an achromatic and athermal system with cost-effective material selection, over the specified temperature and waveband ranges.

• Journal of Information Technology Applications and Management
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• 제30권6호
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• pp.53-68
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• 2023

Through the COVID-19 pandemic, the demand for non-face-to-face communication systems has surged, leading to an increased prevalence of virtual interactions across various domains, such as tasks, meetings, orders and deliveries, and even student education. Against this backdrop, interest in the metaverse platform has been on the rise, with metaverse services like Zepeto, Roblox, and Minecraft expanding beyond gaming to encompass educational fields as well. This study aims to identify authenticity factors influencing metaverse platform-based educational services and examine their impact. The authenticity components are defined as integrity, empathy, interactivity, presence, and uniqueness. The study investigates the effects of these authenticity components on both service value and service satisfaction. To achieve this, a survey involving 320 metaverse users was conducted, and the model was subjected to statistical validation. The findings of this research underscore that perceiving metaverse education services, still in the early stages of introduction, as authentic educational methods for learners positively influences satisfaction with the educational service.This study holds significance as it lays the theoretical groundwork for enhancing the authenticity of educational services in virtual space. It defines and proposes authenticity elements for customer satisfaction in metaverse educational services, which are still in their nascent stages. Moving forward, it is anticipated that various studies will be conducted to enhance the value of metaverse education services and achieve higher customer satisfaction as customer experiences evolve and deepen.