• Journal of Korean Academy of Nursing
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• v.37 no.4
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• pp.613-623
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• 2007

Purpose: The purpose of this study was to describe the operation, staffing, and services provided at adult day care centers in Korea. Methods: The study was a cross-sectional descriptive survey. The subjects were 209 centers among 280 centers registered in Korea (response rate 74.6%). The data was collected from August to December in 2006. Results: 48.8% of centers were located in a city area. The centers were based on the Social Model 65.5% of the centers were open Monday to Friday, an average of $7{\sim}8$ hours per day Dementia, stroke or frail elderly could use the center, and 57.4% of centers were used for dementia and stroke elderly together. The enrollment of elderly was 13.5. The number of total staff was 8.27, the number of RN's and social workers was 0.67, and 2.54 respectively. The social services(Meal preparation 98.6%, Special event 98.1%, Transportation, 97.1%) were provided more than the health services(Physical therapy 98.1%, ADL training 95.2%, Counseling 84 7%, Vaccination 82.8%, Health monitoring 78.9%, Health education 78.5%, Bathing 66.1%, and Speech therapy 28.2%). Conclusion: These results suggest we have to develop a health-focused adult day health care model based on the needs of elderly and their families. Nurses will have an important role in adult day health care.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.129-135
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• 2015

This study, in the operation of street lamp, suggests appropriate algorithm to extend the number of days of street lamp operation as much as possible if the number of sunless days continues and experimentally determines the value of Weather Factor necessary for this algorithm. This is conducted by reducing electricity consumption and securing battery remains through the use of standby power mode, in which maximum amount of light is maintained if there is a pedestrian, and constant brightness is maintained without utilizing maximum electric power if no pedestrians exist, with the application of WFactor value created by the algorithm considering weather forecast and amount of sunlight.

• Journal of Educational Research in Mathematics
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• v.13 no.1
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• pp.25-55
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• 2003

In the school mathematics, the negative numbers have been instructed by means of intuitive models(concrete situation models, number line model, colour counter model), inductive-extrapolation approach, and the formal approach using the inverse operation relations. These instructions on the negative numbers have caused students to have the difficulty in understanding especially why the rules of signs hold. It is due to the fact that those models are complicated, inconsistent, and incomplete. So, students usually should memorize the sign rules. In this study we studied on the didactical phenomenology of the negative numbers as a foundational study for the improvement of teaching negative numbers. First, we analysed the formal nature of the negative numbers and the cognitive obstructions which have showed up in the historic-genetic process of them. Second, we investigated what the middle school students know about the negative numbers and their operations, which they have learned according to the current national curriculum. The results showed that the degree they understand the reasons why the sign rules hold was low Third, we instructed the middle school students about the negative number and its operations using the formal approach as Freudenthal suggest ed. And we investigated whether students understand the formal approach or not. And we analysed the validity of the new teaching method of the negative numbers. The results showed that students didn't understand the formal approach well. And finally we discussed the directions for improving the instruction of the negative numbers on the ground of these didactical phenomenological analysis.

• Journal of Mechanical Science and Technology
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• v.17 no.8
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• pp.1234-1245
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• 2003

An experimental study was carried out to investigate the reduced frequency effect on the near-wake of an elliptic airfoil oscillating in pitch. The airfoil was sinusoidally pitched around the center of the chord between -5$^{\circ}$and ＋25$^{\circ}$angles of attack at an airspeed of 3.4 m/s. The chord Reynolds number and reduced frequencies were 3.3 ${\times}$10$^4$, and 0.1, 0.7, respectively Phase-averaged axial velocity and turbulent intensity profiles are presented to show the reduced frequency effects on the near-wake behind the airfoil oscillating In pitch. Axial velocity defects in the near-wake region have a tendency to increase in response to a reduced frequency during pitch up motion, whereas it tends to decrease during pitch down motion at a positive angle of attack. Turbulent intensity at positive angles of attack during the pitch up motion decreased in response to a reduced frequency, whereas turbulent intensity during the pitch down motion varies considerably with downstream stations. Although the true instantaneous angle of attack compensated for a phase-lag is large, the wake thickness of an oscillating airfoil is not always large because of laminar or turbulent separation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.162-168
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• 2007

This paper presents the effects of thermoelectric module arrangement on the cooling performance of an air conditioner using thermoelectric module. A prototype of air cooling system, employing several thermoelectric modules, has been designed and built. The evaporative cooling technique is adopted for hot side of the module. The number of thermoelectric module in the system has been varied in the range of $2{\sim}8$. The optimal operation conditions, such as input power to the thermoelectric module, fans and pump, have been determined for each arrangement of the system and the cooling performance has been compared under the optimal operation. It is found that both cooling capacity and COP are increased as the number of thermoelectric module increased. It is also found that cooling capacity can be improved by connecting the thermoelectric modules in series than in parallel, while the COP is little affected.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1054-1056
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• 2017

The Preparation for a flight test of the launch vehicle to verify the performance of the liquid rocket engine(LRE) is proceeding. Flight test of liquid rocket engine costs an enormous amount of money, has a restriction on measurement channels, so it requires the optimal measurement plan to check the prelaunch operation and determine the cause of abnormal situation. This paper surveys the foreign sources for LRE flight test. In recent years, as the tendency to eliminate all faults of LRE at the ground test the number of flight test is decreasing and in contrast, the number of measurements and measurement accuracy is increasing. This paper may be used as a reference for the preparation of an LRE flight test.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.2
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• pp.179-187
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• 2020

The FBC(Fixed-Base Comb) is a method to efficiently operate scalar multiplication, a core operation for signature generations of the ECDSA(Elliptic Curve Digital Signature Algorithm), utilizing precomputed lookup tables. Since the FBC refers to the table depending on the secret information and the values of the table are publicly known, an adversary can perform HCA(Horizontal Correlation Analysis), one of the single trace side channel attacks, to reveal the secret. However, HCA is a statistical analysis that requires a sufficient number of unit operation traces extracted from one scalar multiplication trace for a successful attack. In the case of the scalar multiplication for signature generations of ECDSA, the number of unit operation traces available for HCA is significantly fewer than the case of the RSA exponentiation, possibly resulting in an unsuccessful attack. In this paper, we propose an improved HCA on lookup table based scalar multiplication algorithms such as FBC. The proposed attack improves HCA by increasing the number of unit operation traces by determining such traces for the same intermediate value through collision analysis. The performance of the proposed attack increases as more secure elliptic curve parameters are used.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.461-466
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• 2011

The purpose of this study is basically for the use of simulations to enhance productivity. In this paper, the optimal number of allocation in a small and medium industry which produces eleutherococcus senticosus sap, is performed using simulations. The simulation model was developed under considerations of production layout, process & operation, process time, total work time, work in process (WIP), utilization, failure rate, and operation efficient as inputs, and was validated with careful comparisons between real behaviors and outputs of the production line. Therefore, we can evaluate effects and changes in productivity when some strategies and/or crucial factors are changed. Although too many workers and machines could decrease productivity, the eleutherococcus senticosus sap production line in this paper has been maintained many machines. To solve this problem, we determined the optimal number of workers and machines that could not cause any interrupt in productions using simulations. This simulation model considers diverse input variables which could influence productivity, and it is very useful not only for the production line of Eleutherococcus Senticosus Sap, but also for other production lines with various purposes, especially, in the small and medium industries.

• Journal of KIBIM
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• v.3 no.4
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• pp.1-10
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• 2013

In order to boost productivity and efficiency of architectural design, architect accumulates materials and details which are repeatedly used. According as introduction and application of BIM (Building Information Modeling) have proliferated, a number of data are being produced. BIM data constructed in a stage of architectural design reduces repetitive works of design and can be used in estimate and construction, maintenance. BIM library gathered these data are able to enhance participants collaboration and design improvement. Library is a vital factor in BIM and a number of libraries are needed as BIM introduction and application have proliferated in architecture industry. However, BIM Library establishment and related research development are incomplete. And specific standard setting and institutional environment for BIM library building have not been achieved. As such a vast amount of information are generated but there is no systematic plan and reuse frequency is low. So it is necessary to build system for effective data sharing and operation management. In this study, through establishment of BIM standard system and construction of management environmental system, it has an object in view for developing framework which can efficiently manage various libraries happened in BIM architectural design field.

• Journal of Gastric Cancer
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• v.17 no.3
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• pp.237-245
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• 2017

Purpose: Senior surgeons prefer open gastrectomy (OG), while young surgeons prefer laparoscopic gastrectomy (LG). The purpose of this study was to evaluate the surgical outcomes of LG performed by a senior surgeon who was an expert in OG during his learning period, by comparing them with LGs performed by a young surgeon. Materials and Methods: A senior surgeon performed 50 curative gastrectomies with laparoscopy (LG-S group) from March 2015 to August 2016. A young surgeon's initial 50 LGs comprised the LG-Y group. Clinicopathological characteristics and surgical outcomes were compared between the LG-S and LG-Y groups. Results: D2 lymphadenectomy was more frequently performed in the LG-S group than in the LG-Y group (P=0.029). The operation time and number of retrieved lymph nodes did not significantly differ between the 2 surgeons (P=0.258 and P=0.410, respectively). Postoperative hospital stay and postoperative complication rate were similar between 2 groups (P=0.234 and P=1.000, respectively). Similarly, significant decreases in operation time with increasing case numbers were observed for both surgeons, whereas the number of retrieved lymph nodes increased significantly in the LG-Y group but not in the LG-S group. Conclusions: The LG outcomes when performed by the senior surgeon were comparable to those when performed by the young surgeon, despite performing more extended lymphadenectomies. Senior surgeons who are experts in OG should not refrain from performing LG.