• The Journal of the Korean dental association
• /
• 제12권4호
• /
• pp.241-244
• /
• 1974

The author measured the masticatory efficiency in the 50 children with normal sound dentition, in the 20 children with amalgam filling and in the 20 children with fixed type space maintainer i.e. in the 90 children in total and got the following results. 1. the masticatory efficiency were 53.8% in children with normal sound primary dentition. 2. The masticatory efficiency 48.3% in children with amalgam filling and 40.0% in children with fixed type space maintainer 3. The masticatory efficiency of children were 60.0% of adult's in normal dentition.

• Journal of the Korean Institute of Telematics and Electronics
• /
• 제26권2호
• /
• pp.18-28
• /
• 1989

In this paper, we describe a pointing accuracy establishment and efficiency measurement of 13.7 m antenna for observing cosmic radio wave which is in the first stage just after finishing its installation. The initial stage of pointing model, 1 and 2 were set up with the observational data of Sun and Moon which are large in visual diameter and also strong in radio intensity. Based on this model, model 3 and 4 were established within the available operational range, i.e., 3.8" in azimuth deviation, 10.5" in elevation deviation, with the observational data of SiO maser source which is a point source and distributed in overall sky. Both apeture efficiency anhd beam efficiency were measured by observing Venus whose brightness temperature is well-known. The resulting corrected efficiencies were 35% and 50% respectively.

• Journal of the Korean Institute of Educational Facilities
• /
• 제16권5호
• /
• pp.11-18
• /
• 2009

This study examines the issue of space management of university facilities by an assessment model as part of efforts to deal with the crisis of universities. To this end, the study addressed efficiency issue and structural problems using assessment model factors, with the aim of figuring out legitimacy and allocating methods for this purpose. Selected model factors included utilization ratio, residual ratio, vacancy ratio, and occupancy ratio, while for the latter, we investigated into the present situations of space use, focusing on construction, design, and living dimensions. As a result, the study suggested that in the future universities will resort to extension and rebuilding or new building for their facilities. To ensure space efficiency without conflict, we should follow legitimacy of space allocation and composition, building quality university facilities, creating quality environment, preventing tuition from rising or Improving welfare to keep pace with the new era.

• Current Optics and Photonics
• /
• 제6권1호
• /
• pp.23-31
• /
• 2022

Heterodyne efficiency is an indicator to evaluate the performance of space coherent laser communication systems. It is affected by signal light and local oscillator (LO) light amplitude, phase and polarization state. In this paper, based on the common heterodyne efficiency, a heterodyne efficiency model that can reflect polarization aberration of optical system is proposed. The heterodyne efficiency is analyzed when the signal light and the LO light are linearly polarized or circularly polarized. For a coherent communication optical system, when the incident signal light is right-circularly polarized light and the incident LO light is 45° linear polarized light. Based on the three-dimensional ray tracing theory and the heterodyne efficiency proposed in this paper, the change of polarization states and the distribution of heterodyne efficiency of the signal light and LO light influenced by the optical system's polarization aberration are analyzed. Analysis shows that the heterodyne efficiency model proposed in this paper can be used to evaluate coherent communication systems and reflect the influence of optical system polarization aberration.

• ETRI Journal
• /
• 제30권6호
• /
• pp.871-873
• /
• 2008

In this letter, we investigate the spectral efficiency of IEEE 802.22 wireless regional area network (WRAN) spectrum overlay when it is used in TV white space. Since 2004, when the FCC published the notice of proposed rule making 04-186 to make use of unused TV spectrum, the IEEE 802.22 working group has been standardizing specifications for WRAN operations. There have been a few papers investigating the spectral efficiency of this, but their analyses were limited to the cases for various guard distances between WRAN base stations. Since WRAN base station (BS) power for WRAN service may differ from country to country, it is important to analyze the spectral efficiency for various WRAN BS powers. In this letter, we analyze the spectral efficiency of WRAN spectrum overlay as a function of the power of WRAN BSs. The simulation results show that spectral efficiency decreases as the power of WRAN BSs and guard distances increase.

• The Korean Journal of Air & Space Law and Policy
• /
• 제14권
• /
• pp.111-132
• /
• 2001

• Transactions of the Korean Society of Mechanical Engineers A
• /
• 제22권1호
• /
• pp.170-176
• /
• 1998

In this paper, the column space and null space of the Jacobian matrix were obtained by using the pseudo-inverse method and projection matrix. The equations of motion of the system were replaced by independent acceleration components using the null space matrix. The proposed method has the following advantages. (1) It is simple to derive the null space. (2) The efficiency is improved by getting rid of constrained force terms. (3) Neither null space updating nor coordinate partitioning method is required. The suggested algorithm is applied to a three-dimensional vehicle model to show the efficiency.

• Structural Monitoring and Maintenance
• /
• 제7권3호
• /
• pp.261-281
• /
• 2020

Civil structures may experience progressive deterioration and damage under environmental and operational conditions over their service life. Finite element (FE) model updating method is one of the most important approaches for damage identification in structures due to its capabilities in structural health monitoring. Although various damage detection approaches have been investigated on structures, there are limited studies on large-sized space structures. Thus, this paper aims to investigate the applicability and efficiency of sensitivity-based FE model updating framework for damage identification in large space structures from a distinct point of view. This framework facilitates modeling and model updating in large and geometric complicated space structures. Considering sensitivity-based FE model updating and vibration measurements, the discrepancy between acceleration response data in real damaged structure and hypothetical damaged structure have been minimized through adjusting the updating parameters. The feasibility and efficiency of the above-mentioned approach for damage identification has finally been demonstrated with two numerical examples: a flat double layer grid and a double layer diamatic dome. According to the results, this method can detect, localize, and quantify damages in large-scaled space structures very accurately which is robust to noisy data. Also, requiring a remarkably small number of iterations to converge, typically less than four, demonstrates the computational efficiency of this method.

• Korean Institute of Interior Design Journal
• /
• 제13권5호
• /
• pp.143-153
• /
• 2004

This research aimed to assess nursing homes for the elderly with geriatric diseases in Japan, and to prepare the knowledge basis to develop nursing home for the elderly with geriatric diseases in Korea. For this, researcher visited 5 facilities in Tokyo from October 3 to October 9 in 2002, collected data by observations, interviews, and visual materials by taking photographs. Visual materials were analyzed according to the environmental assessment matrix consisted of supportiveness, flexibility, efficiency in perception, accessibility, safety, amenity, and social Interaction that were assorted and were given a name by these researchers in the process of this research. Among the characteristics of environmental design of the analysis cases, 992 items picked out from 722 visual materials were used in the analysis. The data were analyzed using the frequency and percentage with SPSS 11 program. The analysis results were the fellowing. The characteristics of recent nursing home design in Japan tended to focus on supportiveness, amenity, and efficiency in perception but to leave much desired in flexibility and safety. In each space, space to support outdoor activities tended to focus on efficiency in perception, space to support living activities tended to focus on amenities, space to support treatment and living tended to focus on supportiveness, space to support administration and operation tended to focus on supportiveness, and space to support movement tended to focus on amenities.

• Journal of the korean Society of Automotive Engineers
• /
• 제3권1호
• /
• pp.46-53
• /
• 1981

This paper describes emission control of hydrocarbon and carbon-monoxide due to oxidizing catalyst. The experiment was performed on a precious metal pelleted catalyst(Pt). The factors of the efficiency for purification due to oxidizing catalyst are space velocity, temperature, composition of exhaust gas and supplementary air. The experiment was carried out to control the factors of efficiency for purification. The results of experimental study show that temperature of catalytic converter, supplementary air and space velocity affected the efficiency for purification of hydrocarbon and carbon monoxide.