• 한국정밀공학회지
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• 제19권9호
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• pp.172-178
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• 2002

One of the ever-increasing demands on the performances of heterodyne interferometers is to improve the measurement resolution, of which current state -of-the-art reaches the region of sub-nanometers. So far, the demand has been met by increasing the clock speed that drives the electronics involved fur the phase measurement of the Doppler shift, but its further advance is being hampered by the technological limit of modem electronics. To cope with the problem, in this investigation, we propose a new scheme of phase -measuring electronics that reduces the measurement resolution without further increase in clock speed. Our scheme adopts a super-heterodyne technique that lowers the original beat frequency to a level of 1 MHz by mixing it with a stable reference signal generated from a special phase- locked-loop. The technique enables us to measure the phase of Doppler shift with a resolution of 1.58 nanometer at a sampling rate of 1 MHz. To avoid the undesirable decrease in the maximum measurable speed caused by the lowered beat frequency, a special form of frequency up-down counting technique is combined with the super-heterodyning. This allows performing required phase unwrapping simply by using programmable digital gates without 2n ambiguities up to the maximum velocity guaranteed by the original beat frequency.

• 한국조리학회지
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• 제14권2호
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• pp.225-236
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• 2008

This study is to explore how the employees of tourist hotels perceive moderate room rates and price acceptance. Sampling was taken among employees for deluxe hotels at Yusong in Daejeon. A total of 150 samples were distributed and 124 valid samples were selected for this research. Answers were processed by SPSS 15.0 after data coding. The results of study are as follows; First, annual average sales price of hotel rooms is \99,223, and the rack rates take up 49.7% of the transaction rates. Second, the rack rates which many employees think moderate are in the range of $50.09{\sim}75.13%(\100,000{\sim}150,000)$ of the rack rates. Third, many employees consider $40.07{\sim}50.09%(\80,000{\sim}100,000)$ of the rack rates as the moderate acceptability rates. Finally, the differences of fair rates by age and annual income were noticeable. These hotels ought to narrow the gap between rack rates and transaction rates. This study has a meaning to draw up a new plan for the room rate policy.

• Environmental Engineering Research
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• 제24권4호
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• pp.582-590
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• 2019

Currently, the waterfront facility was constructed in New Songdo City, South Korea. It has the various water leisure areas and especially an artificial urban canal with filtered seawater by re-circulating flow system. However, due to excessive amount of nutrients from seawater combined with complicated geometry, it is highly vulnerable to deterioration of water quality. In this study, flow characteristics and pollutant transport were analyzed with comprehensive numerical models, MIKE 3 FM and ECO-lab. Based on these numerical results, notable sampling points were selected for field measurements and comparison between modeling and measured results were conducted. In addition, the integrated water quality evaluation index, Water Quality Index was applied to analyze various water quality issues. We also set up scenarios to control the two kinds of water quality factors, dissolved oxygen (DO), and total phosphorus (TP). As a result, the effect of 20% reduction of TP was less than 10% and it was almost ineffective for a year but it was reduced by up to 40% in case of scenario which DO is increased by 20%. Therefore, it was recommended to control the DO concentration, usually by applying re-aeration facility, rather than TP in artificial urban canal with seawater.

• 한국환경보건학회지
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• 제1권1호
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• pp.5-8
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• 1974

A survey was carried out in order to figure out of phenomenon of increasing and decreasing rate of WBC during a day in normal and healthy person from Oct. 1, 1972 to Nov. 31, 1972. For this survey, it was classified by two groups 50 male students and 35 female students who are from 18 to 25 years old. The blood sampling was collected by thin smear method 8 times from 7:30 A.M. to 10:30 P.M. by 2 hours intervals and calculated by direct manual method. As the results of this survey, the following conclusions were obtained 1) Number of WBC was the lowest degree during the forenoon, and it was the highest degree around the midnight. It was increase from around the noon up to the midnight and decrease from the midnight up to around the noon. 2) Increasing and decreasing curve of WBC of male and female was keeping same pace with both sex in a day. 3) Increase and decrease of lymphocyte and eosinophil was keeping almost same pace with WBC. 4) Increasing rate of number of monocyte was more speedily increasing during the afternoon than the night.

• 대한전자공학회논문지
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• 제12권3호
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• pp.20-25
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• 1975

추상고정 loop (PLL)를 사용하여 안정화시킨 징파 발진기를 개발하였다. 체내제작이라는 관점에서 특수 기봉가공을 한 특수자재 cavity를 사용한 자파수 안정화보다 PLL방법을 채택하였다. 입력 주파수가 다른 두 신호과 위상을 직접 비교할 수 있는 위상검파기로서 sampler와 저주파 filter를 사용할 수 있음을 보였으며, 이 목적에 맞는 약 4 GHz 대까지 sample 할 수 있는 sampler를 개발하였다. 2.16 GHz 대에서 출력이 120mW 이상인 징파발진기를 VCO로 사용하고, 110MHz대에서 발진하는 수품판 발진기를 기준발진기로서 사용한 PLL system으로 약 10-6 정도의 주파수 안정도를 얻을 수 있었다. 발진기 system의 capturing range는 search oscillator를 사용함으로써 lock-in-range인 10MHz대를 얻을 수 있었다.

• 한국산업융합학회 논문집
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• 제21권5호
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• pp.219-225
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• 2018

In this paper, for the testing of tensile strength of dead-end clamp used in transmission line, resulting values were estimated by designing and producing the horizontal version of widely-used vertical tensile tester. Tensile strength test of dead-end clamp for transmission line is essential for quality test of products. Moreover, tensile tester is an equipment that requires high level of reliability which needs to be examined through sampling tests commensurate with total inspection. Frames of tensile tester were made up of H-beams so that it can endure more than 20 [tons] of load capability and the test was implemented for 60[seconds] applying five types of tension. In consequence, the tester could withstand up to 21,600[kg] of weight as well as all types of tension. This newly developed horizontal tensile tester can be utilized in figuring out properties of various materials by estimating tensile strength of materials such as metal, rubber and fiber.

• Safety and Health at Work
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• 제13권2호
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• pp.235-239
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• 2022

Background: The purpose of present study was to determine the effectiveness of training program based on job stress management in NEDSA and line staff. Methods: The study method of this study was quantitative and quasi-experimental research Methods: From the statistical population (all employees of the NEDSA and line staff in 2020-2021), 30 of these people were selected by judgmental sampling method and considering the inclusion and exclusion criteria. The participants were first matched based on age and education and were randomly divided into experimental and control groups. First, pre-test was taken from both groups (Job Stress Questionnaire). The experimental group was presented with a job stress management training package and no protocol was presented in the control group. After the sessions, post-test was received from both groups (experimental and control). After two months, a follow-up test was performed. Results: The results were entered into SPSS-24 software and analyzed. The results of repeated measure showed high effectiveness of the job stress management package (researcher-made). The results showed that the job stress management training package showed 67.5% effectiveness and also the training effect of job stress management training was stable for two months (follow-up). Conclusion: Based on these results, Training program based on stress management can be effective in military staff.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권7호
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• pp.2328-2344
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• 2022

2D human pose estimation still faces difficulty in low-resolution images. Most existing top-down approaches scale up the target human bonding box images to the large size and insert the scaled image into the network. Due to up-sampling, artifacts occur in the low-resolution target images, and the degraded images adversely affect the accurate estimation of the joint positions. To address this issue, we propose a multi-resolution input feature fusion network for human pose estimation. Specifically, the bounding box image of the target human is rescaled to multiple input images of various sizes, and the features extracted from the multiple images are fused in the network. Moreover, we introduce a guiding channel which induces the multi-resolution input features to alternatively affect the network according to the resolution of the target image. We conduct experiments on MS COCO dataset which is a representative dataset for 2D human pose estimation, where our method achieves superior performance compared to the strong baseline HRNet and the previous state-of-the-art methods.

• 한국보건간호학회지
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• 제37권1호
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• pp.111-124
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• 2023

Purpose: This study aimed to investigate the effects of restorative family circles (RFCs) on empowerment and family support for people with mental illness, and the belief system and caring experience of their families. Methods: This study used a quasi-experiment with a non-equivalent control group pretest-posttest non-synchronized design. Ninety-two dyads of patient-family caregivers were recruited using convenience sampling and assigned to the experimental and control groups. The subjects of the experimental group participated in RFCs consisting of eight 90-minute sessions. Data were collected at three different times (pretest, posttest, follow-up test) and analyzed for the effects of RFC using the 𝑥² test, Fisher's exact test, Mann-Whitney U test for homogeneity between groups, and generalized estimating equation models. Results: The findings of this study showed that there were significant differences in the family support for people with mental illness between the pretest and follow-up test, and also in the belief system and caring experience of the family between the pretest and posttest. Conclusion: This study revealed that family interventions based on restorative justice emphasizing community-driven conflict management could be used in psychiatric mental health nursing care for fostering a cohesive family relationship.

• Current Optics and Photonics
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• 제8권1호
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• pp.30-37
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• 2024

Implemented at the Geochang Observatory in South Korea, our slope detection and ranging (SLO-DAR) system features a 508 mm Cassegrain telescope (f /7.8), incorporating two Shack-Hartmann wave-front sensors (WFS) for precise measurements of atmospheric phase distortions, particularly from nearby binary or double stars, utilizing an 8 × 8 grid of sampling points. With an ability to reconstruct eight-layer vertical atmospheric profiles, the system quantifies the refractive index structure function (C_n²) through the crossed-beam method. Adaptable in vertical profiling altitude, ranging from a few hundred meters to several kilometers, contingent on the separation angle of binary stars, the system operates in both wide (2.5 to 12.5 arcminute separation angle) and narrow modes (11 to 15 arcsecond separation angle), covering altitudes from 122.3 to 611.5 meters and 6.1 to 8.3 kilometers, respectively. Initial measurements at the Geochang Observatory indicated C_n² values up to 181.7 meters with a Fried parameter (r₀) of 8.4 centimeters in wide mode and up to 7.8 kilometers with an r₀ of 8.0 centimeters in narrow mode, suggesting similar seeing conditions to the Bohyun Observatory and aligning with a comparable 2014-2015 seeing profiling campaign in South Korea.