• 제목/요약/키워드: digital appliance

검색결과 257건 처리시간 0.033초

오일 용해도를 고려한 $CO_2$ 트윈 로타리 압축기 성능해석 (Solubility Consideration in Performance Analysis of a $CO_2$ Twin Rotary Compressor)

  • 김우영;안종민;김현진;조성욱
    • 설비공학논문집
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    • 제19권12호
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    • pp.842-849
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    • 2007
  • For a $CO_2$ two-stage twin rotary compressor used for heat pump water heater system, changes of $CO_2$ solubility in PAG oil were investigated along the gas passages from the first stage suction to final discharge. Only slight changes in solubility took place in suction chambers for both of the first and second stages, but for compression chambers, solubility variation ranged from 0.115 to 0.136, and from 0.133 to 0.182, respectively for the first and second stages. Calculation of gas flashing in parts of leakage oil flows and of oil contained in control volumes due to solubility changes was conducted and included in gas pressure calculation. For the second stage, gas flashing amounts to around $5%\sim6%$ for most leakage flows. Cooling capacity, compressor input, and COP obtained by calculation were well compared to the experimental results. Effects of operation speed on the compressor performance was also studied: as the shaft speed increased, adiabatic efficiency decreased rapidly due to increased over-compression loss.

$CO_2$ 2단 트윈 로타리 압축기 성능해석 (Performance Analysis of a $CO_2$ Two-Stage Twin Rotary Compressor)

  • 김우영;안종민;김현진;조성욱
    • 설비공학논문집
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    • 제19권1호
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    • pp.19-27
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    • 2007
  • Analytical investigation on the performance of a two stage twin rotary compressor for $CO_2$ heat pump water heater system has been carried out. A computer simulation program was made based on analytical models for gas compression in control volumes, leakages among neighboring volumes, and dynamics of moving elements of the compressor. Calculated cooling capacity, compressor input, and COP were well compared to those of experiments over the compressor speeds tested. For the operating condition of suction pressure of 3 MPa, and discharge pressure of 9 MPa, and compressor inlet temperature of $35^{\circ}C$, the compressor efficiency was calculated to be 80.2%: volumetric, adiabatic, and mechanical efficiencies were 88.3%, 93.2%, and 92.7%, respectively. For the present compressor model, volumetric and adiabatic efficiencies of the second stage cylinder were lower by about $6{\sim}7%$ than those of the first stage mainly due to the smaller discharge port at the second stage. Parametric study on the discharge port size showed that the compressor performance could be improved by 3.5% just by increasing the discharge port diameter by 20%.

EL/IX 단계 3을 적용한 실시간 운영체제 Qplus-P용 C 표준 라이브러리의 설계 및 구현 (The Design and Implementation of EL/LX level3 C Standard Library for RTOS Qplus-P)

  • 김도형;신창민;박승민
    • 정보처리학회논문지A
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    • 제9A권4호
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    • pp.485-490
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    • 2002
  • 디지털 TV, 인터넷 셋탑박스, 인터넷 전화기 등과 같은 정보가전 제품이 속속 등장하면서 이들 제품의 기능을 제어하는데 필수적인 실시간 운영체제 시장이 크게 성장하고 있다. 한국전자통신연구원에서는 소형의 휴대 정보 단말에서부터 디지털 셋탑박스 및 홈 서버까지 다양한 종류의 정보가전 기기에 공통으로 사용될 수 있는 확장 가능한 표준 실시간 운영체제 Qplus-P를 개발하였다. 본 논문에서는 정보가전용 실시간 운영체제 Qplus-P에 탑재되는 C표준 라이브러리의 설계 및 구현에 대해 기술한다. Qplus-PC표준 라이브러리는 레드햇에서 실시간 운영체제 국제 표준으로 제안된 EL/LX 응용 프로그램 인터페이스 단계에 따라 설계되었다. 그리고 Qplus-P 응용 프로그램 수행에 필요한 Tiny-X, 카페 등을 지원하기 위해 추가적으로 필요한 함수들도 구현되었다. 구현된 C표준 라이브러리는 EL/IX 응용프로그램 인터페이스 단계를 적용하지 않은 C표준 라이브러리보다 라이브러리 크기를 30% 정도 줄일 수 있었다.

CCFL 백라이트 패턴 설계툴 개발에 관한 연구 (A Study on the Development of Pattern Design Tool for CCFL Backlight)

  • 조영창;최병진;윤정오
    • 한국산업정보학회논문지
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    • 제11권2호
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    • pp.79-85
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    • 2006
  • 휴대용 정보기기의 발달은 평판 디스플레이 장비 및 부품 소재의 수요급증으로 이어지고 있으며, 이 중에서 LCD는 LCD TV, 컴퓨터 모니터, 디지털 카메라, CNS(car navigation system), 게임기 등의 다양한 제품으로 그 응용범위가 폭넓어지고 있다. 이와 같이 LCD 시장이 급증함에 따라 LCD 배면조명 모듈인 BLU(backlight unit) 생산을 위한 제조업체들의 수도 크게 증가하였으며, 우수한 품질의 광학적 특성을 갖는 BLU 개발을 위해 광반사면 설계에 관한 연구가 꾸준히 진행되고 있다. 본 연구에서는 경험과 시행착오에 기초하여 수작업에 주로 의존하여 온 기존의 패턴설계환경을 개선하기 위해 CCFL을 광원으로 한 백라이트의 패턴 설계툴을 개발하였다. 본 연구의 검증을 위해 실모델의 백라이트에 대한 광반사면을 설계한 후, BM-7으로 휘도균일도를 측정하였다. 휘도균일도 측정결과, 본 연구의 설계툴을 사용한 BLU가 기존의 설계방식으로 보통 5회 이상의 시도에서 얻을 수 있는 휘도균일도를 1차 시도에서 얻을 수 있었다는 점에서 기존의 설계방식보다 우수한 설계 성능을 보임을 알 수 있었다.

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가정용 고분자 전해질 연료전지 열병합 발전시스템의 급탕 적용을 위한 온수 저장조의 최적 설계에 관한 실험적 연구 (Experimental Investigation on the Optimal Design of Water Tank for Domestic Hot Water Supply using PEMFC Co-generation System)

  • 황유진;안영철;정성일;진근호;이재근
    • 설비공학논문집
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    • 제20권6호
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    • pp.394-399
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    • 2008
  • There are many attempts to use a fuel cell system as a residential power generation system. The purpose of this study is to investigate the optimal design of a water tank for a hot water system when the fuel cell co-generation system is combined with a domestic hot water supply system. The demands of hot water supply per month per home are investigated in Busan for a year. It showed somewhat large differences between the actual demand and the designed demand of hot water, but the actual capacity of hourly averaged hot water demands is analyzed as $60{\ell}/h$ in this study based on the actual demand. The experiments are performed in the various inlet and outlet locations of nozzles, and the hot water consumption rates. The experimental results are showed that the optimal capacity of the water tank is $200{\ell}$ when the thermal efficiency, the storing capacity of hot water and the space for installation are considered.

안드로이드와 아두이노를 이용한 지능형 가전제품 전력 컨트롤 (Intelligent Home appliances Power Control using Android and Arduino)

  • 박성현;김아용;김웅준;배근호;유상근;정회경
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2014년도 추계학술대회
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    • pp.854-856
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    • 2014
  • 일인 다기기 시대에 맞추어 스마트 기기로 다양한 가전제품과 전자기기를 스마트 디바이스를 이용하여 제어 가능하게 출시하고 있다. 또한, 청소로봇과 냉장고, 에어컨, TV 등의 제품 수가 빠르게 증가하고 있으며 이러한 기기들을 이용하여 DLNA(Digital Living Network Alliance) 시스템을 구축하고 있다. 그리고 국내외에서 IoT(Internet Of Things)나 Alljoyn 같은 기술들을 개발 및 제공하고 있다. 하지만 현재 사용하고 있는 가전제품이나 전자기기들은 운영체제가 설치되어있는 제품보다 설치되어있지 않은 제품이 많다. 또한, 스마트 가전제품을 사용하지 않는 사용자는 스마트 가전제품 보다는 기존의 전자제품을 구입하는 경우가 더 많이 발생한다. 본 논문에서는 모바일 기기를 사용하여 사용자가 원하는 데이터를 수치화하고 아두이노 보드에 전송하여 운영체제가 없는 기존의 가전제품도 스마트 기기와 같은 제어를 할 수 있도록 하는 시스템을 제안하고 구현한다.

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Effectiveness of low-level laser therapy in facilitating maxillary expansion using bone-borne hyrax expander: A randomized clinical trial

  • Abdelwassie, Sara Hassan;Kaddah, Mohammed Amgad;El-Dakroury, Amr Emad;El-Boghdady, Dalia;Abd El-Ghafour, Mohamed;Seifeldin, Nouran Fouad
    • 대한치과교정학회지
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    • 제52권6호
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    • pp.399-411
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    • 2022
  • Objective: The objective of this randomized clinical trial was to study the skeletal and dental effects of low-level laser therapy (LLLT) along with a miniscrew-assisted expander (Hyrax) after six months of retention. Methods: After sequence generation, concealed allocation, and implementation, 24 female patients were randomly divided (1:1) into two-groups: bone-borne rapid palatal expansion (BBE) without LLLT (n = 12) and BBE with LLLT (n = 12). Eligibility criteria included female patients aged 10-13 years old with bilateral posterior crossbites. Intraoral and extraoral photographs, cone-beam computed tomography images, and digital study models were obtained before expansion and six months after retention. The 7 mm Hyrax appliance was anchored to four palatal mini-screws, which were activated twice daily for 15 days, then locked and kept in place as a retainer. LLLT was performed in the laser group during expansion and retention, according to the guidelines provided. Results: The records of 24 patients were analyzed. According to the post-retention measurements, both groups showed a significant increase in nasal and maxillary widths and total facial height. In the laser group, the Sella-Nasion-Point A and Point A-Nasion-Point B angles and the interpremolar apical distance were significantly increased. Conclusions: Within the limitations of this study, the results suggest that the parameters and protocol of LLLT do not clinically affect the efficiency of BBE in prepubertal and pubertal patients.

묵은 배추김치의 휘발성 성분 특성 (Characterization of Volatile Compounds in Low-Temperature and Long-Term Fermented Baechu Kimchi)

  • 김지윤;박은영;김영석
    • 한국식생활문화학회지
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    • 제21권3호
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    • pp.319-324
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    • 2006
  • 묵은 배추김치의 휘발성 성분들을 고진공승화법을 이용하여 분리, 농축하였으며, GC-MS로 분석하였다. 총 62가지의 휘발성 성분들이 검출되었으며, 7개의 sulfur-containing compounds, 8개의 terpenes, 5개의 esters, 8개의 acids, 15개의 alcohols, 2개의 nitriles, 2개의 ketones, 11개의 aliphatic hydrocarbons, 4개의 miscellaneous compounds등으로 구성되어 있었다. 이 중 특히, acids인 acetic acid와 butanoic acid가 높은 함량을 나타내었다. 묵은 배추김치에서 향기활성성분을 규명하기 위해 고진공승화법을 이용하여 휘발성 성분들을 분리 및 농축 후 향 추출물 희석분석법으로 flavor dilution(FD) factor($Log_3FD$)를 구하였으며, GC-MS 및 GC-Olfactometry(GC-O)법으로 휘발성 성분들을 동정하였다. 이 결과 묵은 배추김치에서 총 16종의 화합물이 검출되었다. 이중 시큼한 냄새, 군덕내의 특성을 지닌 acetic acid, butanoic acid가 높은 FD factor를 보였으며, acids외에 높은 (FD > 9)를 나타내는 성분들로는 linalool, 2-vinyl-4H-1,3-dithin 등이 있었다.

임베디드 플래시 파일시스템을 위한 순위별 지움 정책 (A Ranking Cleaning Policy for Embedded Flash File Systems)

  • 김정기;박승민;김채규
    • 정보처리학회논문지A
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    • 제9A권4호
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    • pp.399-404
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    • 2002
  • 최근 정보 산업과 이동통신 기술이 발전함에 따라 PDA(personal digital assistant), HPC(hand-held PC), 세탑박스(set-top box), 정보가전 등의 임베디드 시스템(embedded system)이 개발되고 있으며, 이러한 시스템을 운영할 실시간 운영체제(RTOS)와파일시스템의 요구는 필수적이다. 휴대의 용이성과 빠른 접근시간, 저전력을 요구하는 임베드 시스템의 특성상 데이터를 저장하기 위한 저장 매체로 하드디스크(hard disk)를 이용하는 것은 비효율적이며, 플래시 메모리(flash memory)가 주로 사용되고 있다. 플래시 메모리는 비휘발성과 빠른 접근 시간을 갖는 장점이 있지만, 상대적으로 느린 지움 시간과 지움 회수의 한계 등은 극복해야 할 문제점이다. 본 논문에서는 이러한 단점을 보완하기 위해 새로운 순위별 지움 정책을 제안하고 성능평가를 실시한다. 지움 정책의 일반적인 역할은 플래시 메모리 공간의 어디를 언제 지울 것인가를 결정한다. 제안된 순위별 지움 정책은 지우는 비용과 한정된 지움 회수를 고려하여 지우는 광간과 시간을 결정함으로써 플래시 메모리의 수명을 최대한 연장하고 플래시 메모리 접근 및 관리의 성능을 향상시킨다. 제안된 방법은 기존의 Greedy 및 Cost-benefit 방법에 비해 저장 연산 수행에서 10%~50%의 성능 향상을 보인다.

Perceptional Change of a New Product, DMB Phone

  • Kim, Ju-Young;Ko, Deok-Im
    • 마케팅과학연구
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    • 제18권3호
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    • pp.59-88
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    • 2008
  • Digital Convergence means integration between industry, technology, and contents, and in marketing, it usually comes with creation of new types of product and service under the base of digital technology as digitalization progress in electro-communication industries including telecommunication, home appliance, and computer industries. One can see digital convergence not only in instruments such as PC, AV appliances, cellular phone, but also in contents, network, service that are required in production, modification, distribution, re-production of information. Convergence in contents started around 1990. Convergence in network and service begins as broadcasting and telecommunication integrates and DMB(digital multimedia broadcasting), born in May, 2005 is the symbolic icon in this trend. There are some positive and negative expectations about DMB. The reason why two opposite expectations exist is that DMB does not come out from customer's need but from technology development. Therefore, customers might have hard time to interpret the real meaning of DMB. Time is quite critical to a high tech product, like DMB because another product with same function from different technology can replace the existing product within short period of time. If DMB does not positioning well to customer's mind quickly, another products like Wibro, IPTV, or HSPDA could replace it before it even spreads out. Therefore, positioning strategy is critical for success of DMB product. To make correct positioning strategy, one needs to understand how consumer interprets DMB and how consumer's interpretation can be changed via communication strategy. In this study, we try to investigate how consumer perceives a new product, like DMB and how AD strategy change consumer's perception. More specifically, the paper segment consumers into sub-groups based on their DMB perceptions and compare their characteristics in order to understand how they perceive DMB. And, expose them different printed ADs that have messages guiding consumer think DMB in specific ways, either cellular phone or personal TV. Research Question 1: Segment consumers according to perceptions about DMB and compare characteristics of segmentations. Research Question 2: Compare perceptions about DMB after AD that induces categorization of DMB in direction for each segment. If one understand and predict a direction in which consumer perceive a new product, firm can select target customers easily. We segment consumers according to their perception and analyze characteristics in order to find some variables that can influence perceptions, like prior experience, usage, or habit. And then, marketing people can use this variables to identify target customers and predict their perceptions. If one knows how customer's perception is changed via AD message, communication strategy could be constructed properly. Specially, information from segmented customers helps to develop efficient AD strategy for segment who has prior perception. Research framework consists of two measurements and one treatment, O1 X O2. First observation is for collecting information about consumer's perception and their characteristics. Based on first observation, the paper segment consumers into two groups, one group perceives DMB similar to Cellular phone and the other group perceives DMB similar to TV. And compare characteristics of two segments in order to find reason why they perceive DMB differently. Next, we expose two kinds of AD to subjects. One AD describes DMB as Cellular phone and the other Ad describes DMB as personal TV. When two ADs are exposed to subjects, consumers don't know their prior perception of DMB, in other words, which subject belongs 'similar-to-Cellular phone' segment or 'similar-to-TV' segment? However, we analyze the AD's effect differently for each segment. In research design, final observation is for investigating AD effect. Perception before AD is compared with perception after AD. Comparisons are made for each segment and for each AD. For the segment who perceives DMB similar to TV, AD that describes DMB as cellular phone could change the prior perception. And AD that describes DMB as personal TV, could enforce the prior perception. For data collection, subjects are selected from undergraduate students because they have basic knowledge about most digital equipments and have open attitude about a new product and media. Total number of subjects is 240. In order to measure perception about DMB, we use indirect measurement, comparison with other similar digital products. To select similar digital products, we pre-survey students and then finally select PDA, Car-TV, Cellular Phone, MP3 player, TV, and PSP. Quasi experiment is done at several classes under instructor's allowance. After brief introduction, prior knowledge, awareness, and usage about DMB as well as other digital instruments is asked and their similarities and perceived characteristics are measured. And then, two kinds of manipulated color-printed AD are distributed and similarities and perceived characteristics for DMB are re-measured. Finally purchase intension, AD attitude, manipulation check, and demographic variables are asked. Subjects are given small gift for participation. Stimuli are color-printed advertising. Their actual size is A4 and made after several pre-test from AD professionals and students. As results, consumers are segmented into two subgroups based on their perceptions of DMB. Similarity measure between DMB and cellular phone and similarity measure between DMB and TV are used to classify consumers. If subject whose first measure is less than the second measure, she is classified into segment A and segment A is characterized as they perceive DMB like TV. Otherwise, they are classified as segment B, who perceives DMB like cellular phone. Discriminant analysis on these groups with their characteristics of usage and attitude shows that Segment A knows much about DMB and uses a lot of digital instrument. Segment B, who thinks DMB as cellular phone doesn't know well about DMB and not familiar with other digital instruments. So, consumers with higher knowledge perceive DMB similar to TV because launching DMB advertising lead consumer think DMB as TV. Consumers with less interest on digital products don't know well about DMB AD and then think DMB as cellular phone. In order to investigate perceptions of DMB as well as other digital instruments, we apply Proxscal analysis, Multidimensional Scaling technique at SPSS statistical package. At first step, subjects are presented 21 pairs of 7 digital instruments and evaluate similarity judgments on 7 point scale. And for each segment, their similarity judgments are averaged and similarity matrix is made. Secondly, Proxscal analysis of segment A and B are done. At third stage, get similarity judgment between DMB and other digital instruments after AD exposure. Lastly, similarity judgments of group A-1, A-2, B-1, and B-2 are named as 'after DMB' and put them into matrix made at the first stage. Then apply Proxscal analysis on these matrixes and check the positional difference of DMB and after DMB. The results show that map of segment A, who perceives DMB similar as TV, shows that DMB position closer to TV than to Cellular phone as expected. Map of segment B, who perceive DMB similar as cellular phone shows that DMB position closer to Cellular phone than to TV as expected. Stress value and R-square is acceptable. And, change results after stimuli, manipulated Advertising show that AD makes DMB perception bent toward Cellular phone when Cellular phone-like AD is exposed, and that DMB positioning move towards Car-TV which is more personalized one when TV-like AD is exposed. It is true for both segment, A and B, consistently. Furthermore, the paper apply correspondence analysis to the same data and find almost the same results. The paper answers two main research questions. The first one is that perception about a new product is made mainly from prior experience. And the second one is that AD is effective in changing and enforcing perception. In addition to above, we extend perception change to purchase intention. Purchase intention is high when AD enforces original perception. AD that shows DMB like TV makes worst intention. This paper has limitations and issues to be pursed in near future. Methodologically, current methodology can't provide statistical test on the perceptual change, since classical MDS models, like Proxscal and correspondence analysis are not probability models. So, a new probability MDS model for testing hypothesis about configuration needs to be developed. Next, advertising message needs to be developed more rigorously from theoretical and managerial perspective. Also experimental procedure could be improved for more realistic data collection. For example, web-based experiment and real product stimuli and multimedia presentation could be employed. Or, one can display products together in simulated shop. In addition, demand and social desirability threats of internal validity could influence on the results. In order to handle the threats, results of the model-intended advertising and other "pseudo" advertising could be compared. Furthermore, one can try various level of innovativeness in order to check whether it make any different results (cf. Moon 2006). In addition, if one can create hypothetical product that is really innovative and new for research, it helps to make a vacant impression status and then to study how to form impression in more rigorous way.

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