• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.17-17
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• 2004

• Journal of Nutrition and Health
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• v.50 no.6
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• pp.552-564
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• 2017

Purpose: The purpose of this study was to measure energy expenditure (EE) the metabolic equivalents (METs) of 13 common physical activities by using a portable telemetry gas exchange system ($K4b^2$) and to assess the accuracy of the accelerometer (Actigraph $GT3X^+$) by gender in Korean adults. Methods: A total of 109 adults (54 males, 55 females) with normal BMI (body mass index) participated in this study. EE and METs of 13 selected activities were simultaneously measured by the $K4b^2$ portable indirect calorimeter and predicted by the $GT3X^+$ Actigraph accelerometer. The accuracy of the accelerometer was assessed by comparing the predicted with the measured EE and METs. Results: EE (kcal/kg/hr) and METs of treadmill walking (3.2 km/h, 4.8 km/h and 5.6 km/h) and running (6.4 km/h) were significantly higher in female than in male participants (p < 0.05). On the other hand, the accelerometer significantly underestimated the EE and METs for all activities except descending stairs, moderate walking, and fast walking in males as well as descending stairs in females. Low intensity activities had the highest rate of accurate classifications (88.3% in males and 91.3% females), whereas vigorous intensity activities had the lowest rate of accurate classifications (43.6% in males and 27.7% in females). Across all activities, the rate of accurate classification was significantly higher in males than in females (75.2% and 58.3% respectively, p < 0.01). Error between the accelerometer and $K4b^2$ was smaller in males than in females, and EE and METs were more accurately estimated during treadmill activities than other activities in both males and females. Conclusion: The accelerometer underestimated EE and METs across various activities in Korean adults. In addition, there appears to be a gender difference in the rate of accurate accelerometer classification of activities according to intensity. Our results indicate the need to develop new accelerometer equations for this population, and gender differences should be considered.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1837-1860
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• 2020

We propose a general framework for studying resource allocation problem and the tradeoff between spectral efficiency (SE) and energy efficiency (EE) for downlink traffic in power domain-non-orthogonal multiple access (PD-NOMA) and device to device (D2D) based heterogeneous cloud radio access networks (H-CRANs) under imperfect channel state information (CSI). The aim is jointly optimize radio remote head (RRH) selection, spectrum allocation and power control, which is formulated as a multi-objective optimization (MOO) problem that can be solved with weighted Tchebycheff method. We propose a low-complexity algorithm to solve user association, spectrum allocation and power coordination separately. We first compute the CSI for RRHs. Then we study allocating the cell users (CUs) and D2D groups to different subchannels by constructing a bipartite graph and Hungrarian algorithm. To solve the power control and EE-SE tradeoff problems, we decompose the target function into two subproblems. Then, we utilize successive convex program approach to lower the computational complexity. Moreover, we use Lagrangian method and KKT conditions to find the global optimum with low complexity, and get a fast convergence by subgradient method. Numerical simulation results demonstrate that by using PD-NOMA technique and H-CRAN with D2D communications, the system gets good EE-SE tradeoff performance.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.788-792
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• 2005

The effect of docosahexaenoic acid (DHA) on maze-learning ability in aged mice was investigated. Aged mice fed a diet deficient in n-3 fatty acid received a semi-purified diet of 0.5, 1 and 2% DHA-ethyl ester (DHA-EE) for 4 months. Maze-learning ability was assessed at 3 months after the start of the experiment. The time required to reach the maze exit and the number of times that a mouse strayed into blind alleys in the maze were measured in 3 trials conducted at 4-day intervals. The time was significantly less in the DHA-EE 0.5% and DHA-EE 2% groups than in the control group (p<0.05). The number of times mice strayed into blind alleys in the maze was significantly lower in the DHA-EE 2% group than in the control group (p<0.05). Mice fed DHA showed increased DHA and decreased level of arachidonic acid (AA) in the brain. These results suggest that the intake of a 2% DHA diet improves learning ability in aged mice, which is associated with a higher DHA content in the brain.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.401-404
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• 2002

EJB 는 분산 트랜잭션 기반의 엔터프라이즈 어플리케이션을 위한 컴포넌트 컴퓨팅을 위한 아키텍처이다. EJB 는 J2EE 플랫폼을 위한 서버 측 컴포넌트 아키텍처이며, J2EE 플랫폼의 재사용 가능하고 J2EE 기술 중에서 다중 플랫폼 또는 다중 서버에 이식 가능한 비즈니스 로직을 표현하는 코어 기술이다. EJB 기술을 사용하게 되면 응용 로직 개발자들은 시스템 영역의 서비스들 즉, 트랜잭션, 보안, 생명주기, 쓰레딩, 영속성_등의 기능을 직접 구현하지 않고 손쉽게 응용 로직을 개발할 수 있다. 본 논문에서는 J2EE 의 핵심 서버인 EJB 서버 시스템의 설계 사상과 네이밍 및 디렉토리 관리 모듈에 대한 구체적인 설계 방안을 제시한다.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.77-93
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• 2002

Now we are following component-based software development as a solution to improve the reusability, reliability, and extensibility of the software. To support these, the developed components must be reused through component repository at software development. However, traditional centralized repositories couldn't activate component markets since not only the number of users were restricted but also most of the provided components were those on clients like user interface and so on. Recently, a lot of server-side components, reused in a specific domain, have appeared thanks to the development of both Internet technology and component technology such as EJB, DCOM, etc. Therefore, component repositories, based on domain information, classify and provide components and must offer web-based service for many users to use it stably. This study introduces the implementation of a component repository based on J2EE application model. It provides application developers with the service to search and extract appropriate components, and supplies them reliable services in web environment.

• Journal of Chest Surgery
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• v.57 no.2
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• pp.160-168
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• 2024

Background: Data on perioperative outcomes of emergent versus elective resection in esophageal cancer patients requiring esophagectomy are lacking. We investigated whether emergent resection was associated with increased risks of morbidity and mortality. Methods: Data on patients with esophageal malignancy who underwent esophagectomy from 2005 to 2020 were retrospectively analyzed from the American College of Surgeons National Surgical Quality Improvement Program database. Thirty-day complication and mortality rates were compared between emergent esophagectomy (EE) and non-emergent esophagectomy. Logistic regression assessed factors associated with complications and mortality. Results: Of 10,067 patients with malignancy who underwent esophagectomy, 181 (1.8%) had EE, 64% had preoperative systemic inflammatory response syndrome, sepsis, or septic shock, and 44% had bleeding requiring transfusion. The EE group had higher American Society of Anesthesiologists (ASA) class and functional dependency. More transhiatal esophagectomies and diversions were performed in the EE group. After EE, the rates of 30-day mortality (6.1% vs. 2.8%), overall complications (65.2% vs. 44.2%), bleeding, pneumonia, prolonged intubation, and positive margin (17.7% vs. 7.4%) were higher, while that of anastomotic leak was similar. On adjusted logistic regression, older age, lower albumin, higher ASA class, and fragility were associated with increased complications and mortality. McKeown esophagectomy and esophageal diversion were associated with a higher risk of postoperative complications. EE was associated with 30-day postoperative complications (odds ratio, 2.39; 95% confidence interval, 1.66-3.43; p<0.0001). Conclusion: EE was associated with a more than 2-fold increase in complications compared to elective procedures, but no independent increase in short-term mortality. These findings may help guide data-driven critical decision-making for surgery in select cases of complicated esophageal malignancy.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.3
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• pp.270-277
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• 2012

This paper presents a new DAC design strategy to achieve a wideband dynamic linearity by increasing the bandwidth of the output impedance. In order to reduce the dominant parasitic capacitance of the conventional matrix structure, all the cells associated with a unit current source and its control are stacked in a single column very closely (stacked unit cell structure). To further reduce the parasitic capacitance, the size of the unit current source is considerably reduced at the sacrifice of matching yield. The degraded matching of the current sources is compensated for by a self-calibration. A prototype 6-bit 3.3-GS/s current-steering full binary DAC was fabricated in a 1P9M 90 nm CMOS process. The DAC shows an SFDR of 36.4 dB at 3.3 GS/s Nyquist input signal. The active area of the DAC occupies only $0.0546mm^2$ (0.21 mm ${\times}$ 0.26 mm).

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.1
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• pp.23-32
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• 2011

A 40 fJ/c-s, 1 V, 10-bit SAR ADC is presented for energy constrained wearable body sensor network application. The proposed 10-bit dual sampling capacitive DAC topology reduces switching energy by 62% compared with 10-bit conventional SAR ADC. Also, it is more robust to capacitor mismatch than the conventional architecture due to its cancelling effect of each capacitive DAC. The proposed SAR ADC is fabricated in 0.18 ${\mu}m$ 1P6M CMOS technology and occupies 1.17 $mm^2$ including pads. It dissipates only 1.1 ${\mu}W$ with 1 V supply voltage while operating at 100 kS/s.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.183-192
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• 2006

Predicting energy expenditure (EE) is important to prevent work-related musculoskeletal disorders (WMSDs). The problem to predict EE is that the standard of EE is based on western data. The authors checked average EE by job categories to provide basic data for suggesting proper work intensity for Korean workers. This study was conducted from 2003 to 2005. Study subjects were recruited from 4 car parts assembly plant, 2 car assembly plant, 2 Heavy machine manufacturing plant and 2 shipyards. Total study subjects were 515 male workers. To estimate VO2max, sub-maximal test was conducted to measure VO275%max by bicycle ergometer (Combi Co, Aerobike 75XL II). Heartbeats were recorded with heartbeat recorder (Polar Electro Co, Finland, S810) during work. EE of work was calculated by recorded heartbeat and individual regression equation which was derived from sub-maximal test. Subjects were classified into 4 industry and 8 work posture, 23 job task categories. Mean EEs (S.D.) according to industry classification (kcal/min) were 4.9 (0.7), 4.8 (0.7), 4.9 (0.7), 5.0 (0.9), and 4.0 (0.5) for Car Part manufacture, Car Assembly, Ship Building, Heavy Machinery Manufacture, and Hospital Office, respectively. The results suggest that Korean male workers of exceeding to the NIOSH criteria will be needed to plan for job rescheduling to maintain $worker^{\circ}$Øs health. Further study to establish Korean work intensity standard would be needed.