• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.60-65
• /
• 2008

The near-optimal control algorithm for central cooling and heating system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor load and outdoor temperatures. The optimal set-points of control parameters with near-optimal control are supply air and chilled or hot water temperatures. The near optimal control algorithm has been implemented by using LabVIEW program in order to analyze energy performance for central cooling and heating control system.

• 한국지열·수열에너지학회논문집
• /
• 제8권4호
• /
• pp.1-7
• /
• 2012

In this study, computer simulation for demand control strategies to save the electric energy and power price in the building central cooling system is done. The demand control and outdoor reset control algorithms are applied by consideration the electric energy and power price according to the energy consumption characteristics. The suggested control methods show better responses in the power price and energy consumption in comparison with the conventional one.

• Earthquakes and Structures
• /
• 제23권2호
• /
• pp.207-219
• /
• 2022

Seismic response control has always been a grave concern with the damage and collapse of many buildings during the past earthquakes. While there are several existing techniques like base isolation, viscous damper, moment-resisting beam-column connections, tuned mass damper, etc., many of these are succumbing to either of large displacement, near-fault, and long-period earthquakes. Keeping this viewpoint, extensive research on the application of smart materials for seismic response control of buildings was attempted during the last decade. Shape Memory Alloy (SMA) with its unique properties of superelasticity and shape memory effect is one of the smart materials used for seismic control of buildings. In this paper, an exhaustive review has been compiled on the seismic control applications of SMA in buildings. Unique properties of SMA are discussed in detail and different phases of SMA along with crystal characteristics are illustrated. Consequently, various seismic control applications of SMA are discussed in terms of performance and compared with prevalent base isolators, bracings, beam-column connections, and tuned mass damper systems.

• Journal of Power Electronics
• /
• 제16권2호
• /
• pp.542-552
• /
• 2016

Central 60° synchronous modulation is an easy pulse-width modulation (PWM) method to implement for the traction inverters of urban rail trains at a very low switching frequency. Unfortunately, its switching patterns are determined by a Fourier analysis of assumed steady-state voltages. As a result, its transient responses are not very good with over-currents and high instantaneous torque pulses. In the proposed solution, the switching patterns of the conventional central 60° modulation are modified according to the dynamic error between the target and actual stator flux. Then, the specific trajectory of the stator flux and current vector can be guaranteed, which leads to better system transients. In addition, stator flux control is introduced to get smooth mode switching between the central 60° modulation and the other PWMs in this paper. A detailed flow chart of the control signal transmission is given. The target flux is obtained by an integral of the target voltage. The actual PMSM flux is estimated by a minimum order flux state observer based on the extended flux model. Based on a two-level inverter model, improved rules in the α-β stationary coordinate system and equations of the switching patterns amendment are proposed. The proposed method is verified by simulation and experimental results.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권1호
• /
• pp.1-17
• /
• 2016

The separated management and operation of commercial IP/optical multilayer networks makes network operators look for a unified control plane (UCP) to reduce their capital and operational expenditure. Software-defined networking (SDN) provides a central control plane with a programmable mechanism, regarded as a promising UCP for future optical networks. The general control and scheduling mechanism in SDN-based optical burst switching (OBS) networks is insufficient so the controller has to process a large number of messages per second, resulting in low network resource utilization. In view of this, this paper presents the burst-flow scheduling mechanism (BFSM) with a proposed scheduling algorithm considering channel usage. The simulation results show that, compared with the general control and scheduling mechanism, BFSM provides higher resource utilization and controller performance for the SDN-based OBS network in terms of burst loss rate, the number of messages to which the controller responds, and the average latency of the controller to process a message.

• 한국지열·수열에너지학회논문집
• /
• 제7권1호
• /
• pp.38-44
• /
• 2011

In this study, heating performance and energy consumption characteristics with control strategies for central heating system were researched by the simulation. The simulation analysis is made by TRNSYS ver. 15 with the actual data. The parametric study on proportional factor, control time interval and outdoor air temperatures changes were done to compare control characteristics and energy performance, respectively. As a result, the simulation results with various parameter changes show good heating performance and energy saving.

• Journal of Korean Medical Science
• /
• 제33권45호
• /
• pp.280.1-280.9
• /
• 2018

Background: Surveillance and interventions of central line-associated bloodstream infections (CLABSIs) had mainly been targeted in intensive care units (ICUs). Central lines are increasingly used outside ICUs. Therefore, we performed a hospital-wide survey of CLABSIs to evaluate the current status and develop strategies to reduce CLBASI rates. Methods: All hospitalized patients with central venous catheters (CVCs) were screened for CLABSIs from January 2014 through December 2015 at a 1,328 bed tertiary care teaching hospital in Korea using an electronic data-collecting system. Clinical information including type of CVC was collected. CLABSI rates were calculated using the definitions of the National Health and Safety Network after excluding mucosal barrier injury laboratory-confirmed bloodstream infection (BSI). Results: A total of 154 CLABSIs were identified, of which 72 (46.8%) occurred in general wards and 82 (53.2%) in ICUs (0.81 and 2.71 per 1,000 catheter days), respectively. Nontunneled CVCs were most common (68.6%) among 70 CLABSI events diagnosed within one week of their maintenance. On the other hand, tunneled CVCs and peripherally inserted central catheters (PICCs) were more common (60.5%) among 114 CLABSI events diagnosed more than a week after maintenance. Whereas the majority (72.2%) of CLABSIs in ICUs were associated with non-tunneled CVCs, tunneled CVCs (38.9%) and PICCs (36.8%) were more common in general wards. Conclusion: CLABSIs are less common in general wards than in ICUs, but they are more often associated with long-term indwelling catheters. Therefore, interventions to prevent CLABSIs should be tailored according to the type of ward and type of catheter.

• 한국조리학회지
• /
• 제9권4호
• /
• pp.54-68
• /
• 2003

This study aims at efficiency of kitchen management by adoption of a systematic central kitchen and conversion of conventional kitchen to convenience kitchen at ' H ' restaurant. First, integrated menu control of banquet buffet functions became more competitive with quality menu and eventually brought about guests satisfaction. Second, systematic central kitchen made possible standardization and mass production through simplified production line. Efficiency through quick service and shortened preparation time was realized, and food materials were recycled effectively at the same time. Integrated ordering lowered purchasing price and built an efficient cost control system. Third, conversion of conventional kitchen to convenience kitchen and strengthened central kitchen system facilitated agreeable work conditions and optimal work flow with butcher's and even sauce making utensils. Fourth, integrated supply system of buffet menu and sauce from western restaurants saved about 520 million won of labor costs. Last, one integrated kitchen out of two was easier in sanitation control with pleasant restaurant space. Sharing kitchen facilities and equipments also saved about 30% of maintenance fee. Power, water, and gas were also saved and eventually curtailed overall expenses.

• Journal of Oral Medicine and Pain
• /
• 제12권1호
• /
• pp.47-52
• /
• 1987

In order to evaluate the effect of signs and symptoms of temporomandibular disorders on the bite force of anterior teeth, the author estimated a feature of maintaining the maximum bite force on central incisors in Korean 34 adult females with signs and symptoms of temporomandibular disorders (TMD group) and in Korean 31 adult females within normal masticatory function far from any sign or symptom of TMD (control group), and analyzed the data statistically. The obtained results were as follows: 1. There was not a significant difference of the maximum bite force on central incisors between TMD group and control group (P>0.05). 2. The duration of maintaining the maximum bite force on central incisors in TMD group was shorter than it in control group (P<0.01).

• 한국연초학회지
• /
• 제31권2호
• /
• pp.75-84
• /
• 2009

The objective of this study was to investigate the effect of nitrogen compounds such as protein on the chemical composition and toxicity of cigarette mainstream smoke. BSA protein was treated into the tobacco leaf of original 2R4F cigarette at 1~4 % level. The studies were performed which included a bacterial mutagenicity assay and a mammalian cell cytotoxicity assay for total particulate matter(TPM), and glutathione(GSH) consumption assay for gas/vapor phase(GVP) and determination of smoke chemical constitute. Cigarettes treated with protein were observed dose-dependent increase in yield of volatiles, semi-volatiles and aromatic amines compared with control cigarette. However, carbonyl compounds such as acrolein was lower than that of control cigarette when calculated on an equal TPM basis. The cytotoxicity of TPM obtained from the protein-added cigarettes was not different from that of control cigarette. However, the mutagenicity of the TPM from protein-treated cigarettes(1~4 %) was up to 10-27 % higher than that of control. On the other hand, toxicity of GVP from protein-treated cigarette(4 %) was significantly decreased compared with control cigarette. An overall assessment of our data suggests that nitrogen compounds such as protein should be important for the chemical composition and biological activity of cigarette mainstream smoke.