• 제목/요약/키워드: Demand control

검색결과 2,300건 처리시간 0.036초

Exploring the Effect of Mental Demand in Web Searches: A Pilot Study

  • 나경식
    • 한국문헌정보학회지
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    • 제48권2호
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    • pp.379-398
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    • 2014
  • This pilot study explored the effect of mental demand on a Web searcher's thoughts, emotions, efforts, and performance in Web searches in order to address whether or not there is any difference between searchers exposed to mental demand manipulation and searchers not exposed. Research data were collected via think-aloud protocol (TAP) with a dual-task in experiments and interviews with 10 subjects who participated in this study. For the searcher's thoughts, relevance judgment was found to be hindered by mental demand. For the searcher's emotions, the experimental group was more frustrated than the control group. With respect to the searcher's efforts, searchers for the experimental group with mental demand manipulation were more likely to spend more time, make fewer queries, and visit fewer pages but work harder to find more relevant information that they needed. Lastly, with regard to the searcher's performance, it is likely that performance was highly dependent upon the completion of the search tasks for both groups. The NASA-TLX six components and cognitive load scores of searchers did not make a significant difference in the outcome. The findings support the use of a dual-task methodology as a promising approach for the assessment of cognitive load induced by complex Web searches.

Introduction of Automation and Control Issues for Hot Rolling Mill Processes

  • Lee, Duk-Man
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.175.1-175
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    • 2001
  • This paper handles main automation facilities and important control issues for hot rolling mill processes. Starting from the general procedures of production cycle, detailed tension control applications are handled based on field experiences and published research papers. Nowadays, quality control and delivery time control for products is becoming more and more important as the client demand is tighter than any other period. In this respect, control technology in steel making process takes very important position. Therefore, the objective of this paper is to share control problems with the people in academic field and by doing so, to get new and striking solution for the problems.

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물리치료사의 직무관련 근골격계 통증과 직무 스트레스 (Work-Related Musculoskeletal Pain and Job Stress in Physical Therapists)

  • 용준형;이충휘;권오윤;전혜선
    • 한국전문물리치료학회지
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    • 제17권1호
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    • pp.53-61
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    • 2010
  • This study investigated the relationships between Work-related musculoskeletal disorders (WMSDs), contributing factors, and the occupational stress of physical therapists. Self-reported questionnaires were given to 180 physical therapists in Gangwon Province. Variables examined included the prevalence of pain sites related to WMSDs; pain intensity; pain pattern; and job stress, which is thought to involve the physical environment; job demand; insufficient job control; interpersonal conflict; job insecurity; organizational system; reward system; and occupational culture. Among physical therapists, work-related musculoskeletal pain commonly affected the low back (30.1%), shoulder (29.3%), and wrist (12.2%). The sites of work-related musculoskeletal pain treated medically were the low back (22.8%), shoulder (19.8%), neck (12.7%), and wrist (12.1%). "Repeating the same work constantly" was suggested to be the major cause of the pain. The younger therapists were significantly more likely to feel high job stress due to the physical environment (p<.05), job demand (p<.05), and organizational system (p<.01). Women were more likely to feel greater job stress related to job demand, insufficient job control, the organization system, and job rewards. Men were more likely to feel greater job stress related to job insecurity. Weak positive relationships were observed between work-related musculoskeletal pain and job stress, which is thought to involve the physical environment; job demand; insufficient job control; interpersonal conflict; job insecurity; organizational system; reward system; and occupational culture. Physical therapists appear to be at higher risk of WMSDs because 80.1% of the physical therapists studied experienced work-related musculoskeletal pain. To reduce the risk, we need intervention strategies such as preventive education, ergonomically designed medical equipment, a psychosocial approach to work conditions, improved mechanical conditions related to therapeutic patterns, and an institutional infrastructure with sufficient personnel and scheduling.

스마트미터를 활용한 건축물의 전력에너지 절감 및 효율화 방안 (Electric Power Energy Saving and Efficient Measures in Buildings using the Smart-Meter)

  • 황현배;정병수
    • 디지털융복합연구
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    • 제12권11호
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    • pp.365-372
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    • 2014
  • 본 논문에서는 스마트미터를 활용한 건축물의 전력에너지 절감 및 효율화 방안에 대하여 실험하였다. 전력에너지 절감을 위해 개선된 자동역률제어시스템(APFC)을 제안하고, 수요전력의 억제(Demand Control) 방안을 제시하였다. 이는 스마트미터의 ICT 기술을 통하여 실시간 양방향으로 콘덴서 뱅킹과 차단기를 직접 제어함으로써 이루어진다. 개선된 APFC는 콘덴서 뱅킹을 보다 다양화하기 위해 이종 용량의 콘덴서를 직병렬 혼합 결선하여 구성함으로써 구축 비용을 최소화 한다. 상기 기능을 위해 Atmel사의 AVR465를 이용하여 PLC 및 Zigbee 통신기능을 갖는 스마트미터를 설계하였다. 24시간 운영되는 숙박시설에 대하여 테스트한 결과 역률은 95%이상을 유지하였고, 과보상은 발생하지 않았음을 확인할 수 있었다.

Energy and Air Quality Benefits of DCV with Wireless Sensor Network in Underground Parking Lots

  • Cho, Hong-Jae;Jeong, Jae-Weon
    • 국제초고층학회논문집
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    • 제3권2호
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    • pp.155-165
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    • 2014
  • This study measured and compared the variation of ventilation rate and fan energy consumption according to various control strategies after installing wireless sensor-based pilot ventilation system in order to verify the applicability of demand-controlled ventilation (DCV) strategy that was efficient ventilation control strategy for underground parking lot. The underground parking lot pilot ventilation system controlled the ventilation rate by directly or indirectly tracking the traffic load in real-time after sensing data, using vehicle detection sensors and carbon monoxide (CO) and carbon dioxide ($CO_2$) sensor. The ventilation system has operated for 9 hours per a day. It responded real-time data every 10 minutes, providing ventilation rate in conformance with the input traffic load or contaminant level at that time. A ventilation rate of pilot ventilation system can be controlled at 8 levels. The reason is that a ventilation unit consists of 8 high-speed nozzle jet fans. This study proposed vehicle detection sensor based demand-controlled ventilation (VDS-DCV) strategy that would accurately trace direct traffic load and CO sensor based demand-controlled ventilation (CO-DCV) strategy that would indirectly estimate traffic load through the concentration of contaminants. In order to apply DCV strategy based on real-time traffic load, the minimum required ventilation rate per a single vehicle was applied. It was derived through the design ventilation rate and total parking capacity in the underground parking lot. This is because current ventilation standard established per unit floor area or unit volume of the space made it difficult to apply DCV strategy according to the real-time variation of traffic load. According to the results in this study, two DCV strategies in the underground parking lot are considered to be a good alternative approach that satisfies both energy saving and healthy indoor environment in comparison with the conventional control strategies.

종량제봉투 가격이 생활폐기물 배출량에 미치는 영향: 부산광역시 자연실험 사례 (Effect of Pay-as-you-throw Bag Prices on Domestic Waste: Evidence from a Natural Experiment of Busan)

  • 구남규
    • 자원ㆍ환경경제연구
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    • 제31권3호
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    • pp.319-342
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    • 2022
  • 본 연구는 2019년 부산광역시 일부 자치구의 종량제봉투 가격 인하 사례를 이용하여 자연실험 합성집단통제 이중차분법을 통해 종량제봉투 가격이 생활폐기물 배출량에 미치는 영향을 분석했다. 수요 및 가격탄력도를 추정할 때 흔히 발생할 수 있는 내생성 문제를 고려하기 위해 가격 동결 자치구를 합성통제집단으로, 가격 인하 자치구를 처치집단으로 설정하여 분석했다. 분석 결과, 수요의 가격탄력도는 0.05~0.11 수준으로 종량제봉투 가격은 판매량에 거의 영향을 미치지 못했다. 종량제봉투는 필수재적 성격이 강하고 가구 소득에서 차지하는 비중이 매우 작기 때문으로 보인다. 이는 종량제봉투의 수요곡선이 거의 수직에 가까우므로 폐기물 감소 목표 달성을 위해서는 가격정책 보다 수요곡선 자체를 이동시킬 수 있는 정책이 더욱 효과적일 수 있음을 시사한다.

Antibiofilm activity of polyethylene glycol-quercetin nanoparticles-loaded gelatin-N,O-carboxymethyl chitosan composite nanogels against Staphylococcus epidermidis

  • Wanhe Luo;Yongtao Jiang;Jinhuan Liu;Beibei Sun;Xiuge Gao;Samah Attia Algharib;Dawei Guo;Jie Wei;Yurong Wei
    • Journal of Veterinary Science
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    • 제25권2호
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    • pp.30.1-30.16
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    • 2024
  • Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

Bargaining-Based Smart Grid Pricing Model for Demand Side Management Scheduling

  • Park, Youngjae;Kim, Sungwook
    • ETRI Journal
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    • 제37권1호
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    • pp.197-202
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    • 2015
  • A smart grid is a modernized electrical grid that uses information about the behaviors of suppliers and consumers in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity. In the operation of a smart grid, demand side management (DSM) plays an important role in allowing customers to make informed decisions regarding their energy consumption. In addition, it helps energy providers reduce peak load demand and reshapes the load profile. In this paper, we propose a new DSM scheduling scheme that makes use of the day-ahead pricing strategy. Based on the Rubinstein-Stahl bargaining model, our pricing strategy allows consumers to make informed decisions regarding their power consumption, while reducing the peak-to-average ratio. With a simulation study, it is demonstrated that the proposed scheme can increase the sustainability of a smart grid and reduce overall operational costs.

불안정한 주문 패턴의 수요에 대응하는 재고 관리 기법을 응용한 생산계획 수립 방법 (The Way of Production Planning Using the Inventory Control Method, Responding the Demand Fluctuation)

  • 배병곤;조중현;강경식
    • 대한안전경영과학회지
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    • 제9권3호
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    • pp.119-125
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    • 2007
  • As competition in manufacturing enterprise is contested, the scope of safely production planning, manufacturing enterprise should ensure, has been reduced. The more upstream of SCM, the more reduction of scope of production planning. As a result, order fluctuation is more sharply contested. Through improving the logistics network, it is best way that the end user's demand information is conveyed to upstream of SCM, but it is difficult in fact. In this paper, it mention the way of robustic adjustment, in the suppliers' point of view, the end user's demand information is dammed up, as they postpone responding the customer's order as a possible. And it will show the result of appling the way, as a case study.

VOD(Video On Demand) 서비스를 위한 임베디드 네트워크 엔진 (An Embedded Network-Engine for Video On Demand Service)

  • 아미루자만;손성옥;노재춘
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2007년도 한국컴퓨터종합학술대회논문집 Vol.34 No.1 (A)
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    • pp.145-148
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    • 2007
  • Although the embedded network-engine is a demand of time, it is observed that up to this time the network-engines are not sufficient to control the input and output device for Video On Demand (VOD). In this paper we have proposed the wireless network-engine with the capability of controlling the input and output device.

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