• Journal of Chest Surgery
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• v.25 no.3
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• pp.307-314
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• 1992

The internal mammary artery has been advocated for use in bypass grafting owing to its superior long-term patency when compared to saphenous vein grafts. Concern exists that the flow through internal mammary artery may be inadequate during periods of peak myocardial demand when the internal mammary artery graft was used for proximal left anterior descending artery stenosis. This flow adequacy was investigated in 13 consecutive patients with a mean proximal left anterior descending artery stenosis of 84.2% who were selected for coronary bypass using internal mammary artery. We checked flow and diameter of left internal mammary artery without intraluminal dilatation just before anastomosis to left anterior descending artery during cardiopulmonary bypass. Clinical results were evaluated postoperatively with clinical symptoms, echocardiographies, stress tests, and coronary angiographies. The mean internal mammary artery flow measured just before anastomosis was 38ml/ min[range of 20 to 80ml /min] and its mean internal diameter 1.4mm. Maximal workload was improved from preoperative value of 6.3$\pm$2.5METS to postoperative value of 9.1$\pm$1.4 METS in 9 patients who Paired-test can be used. Cardiac symptoms recurred in two patients after bypass surgery, but they were not related to left internal mammary artery grafts. All patients were discharged in postoperatively 9.3 days[range of 7 to 20 days] after operation without mortality. Thus, on the basis of these findings, the internal mammary artery is a reasonable graft that we can routinely use for proximal left descending artery stenosis if internal diameter of the internal mammary artery is more than 1.0mm and its flow is more than 20ml /min at mean arterial pressure of 50 to 60mmHg during cardiopulmonary bypass.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.105-110
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• 2012

Although reinforcement of work intensity caused by the recent prosperity of shipbuilding businesses and the steady increasing of results which produces orders has difficulties with heavy workload, unique work circumstance in shipbuilding industry where main and subcontractor do the job together is not easy to manage its safety systematically. According to KOSHA(Korea Occupational Safety & Health Agency), there were 2, 587 deaths of 95,806 disaster victims a year on average for late 6 years(2003-2008), therein 36,605 disaster victims and 646 death in manufacture where shipbuilding have 2,287 victims, 6.25% of total disaster victims and 45 deaths, 6.97%. Moreover it shows much higher accident rate in shipbuilding industry in Korea than well developed countries in this industry as Japan, Singapore, Taiwan and so it does about 3 to 10 times higher in case of death. Compared to Japan with a shipbuilding competition of orders received system, 2 times and 2.3 times higher for each and it is more than 2 times higher than accident rate of all domestic industries. These increasing of disaster result in a labor-management dispute and it is necessary that more positive efforts and investments because there occurs blind spot, neglected industry safety and health management by lack of them, Therefore this study, for the effective safety and health management of shipbuilding industry, attempts to analyze risk on kinds of ships and budget needed in safety management through classifying ships that are being made recently by three dominate major companies. For this, we carried out a survey and interview targeting experts related to shipbuilding industry and used AHP(Analytic Hierarchy Process) for result analysis. It is considered that cost of safety and health management will be spent more effectively on the results about risk on kinds of ships and budget needed in safety management in the study and that this study can contribute to decreasing disasters in shipbuilding industry.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.19-26
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• 2004

This paper deals with the automatic flight control system for an unmanned target drone which is operated by an army as an anti-air gun shooting training. By automation of unmanned target drone that is manually operated by external pilot, pilot can reduce workload and an army can reduce the budget. Most UAVs which are developed until today use high-cost sensors as AHRS and IMU to measure the attitude, but those are contradictory for the reduction of budget. This paper says the development of low-cost automatic flight control system which makes possible of automatic flight with low-cost sensors. We have developed the integrated automatic flight control system by integrating electricity module, switching module, monitoring module and RC receiver as an one module. We also prove the performance of automatic flight control system by flight test.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.529-536
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• 2017

The general ground control system has control and information display functions for the operation of a single unmanned aerial vehicle. Recently, the function of the single ground control system extends to the operation of multiple UAVs. As a result, operators have been exposed to more diverse tasks and are subject to task overload due to various factors during their mission. This study proposes an adaptive ground control system that reflects the operator's condition through the task overload measurement of multiple UAV operators. For this, the ground control software is developed to control multiple UAVs at the same time, and the simulator with six degree-of-freedom aircraft dynamics is constructed for realistic human-machine-interface experiments by the operators.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.137-147
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• 2008

Recently, Power and thermal management are becoming major concerns in computer system design. The energy efficiency is an important attribute of the mobile and embedded systems. Today's powerful mobile processors needs more energy and longer battery life. Many research has been focused to reduce energy consumption for the mobile processors.In this paper, performance monitoring system for the Power-management techniques is implemented for Intel's XScale microarchitecture-based Marvell PXA320 processor on Windows CE platform. It also provides software interface for changing DVFS configuration. Performance and power consumption are measured for benchmark programs through performance counter value and voltage/current measurements on LabVIEW platform. By using the developed monitoring system, it is possible for dynamic power management to track processor's workload and to determine the actual power consumption.

• Journal of Korean Critical Care Nursing
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• v.6 no.2
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• pp.65-77
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• 2013

Purpose: The purpose of the study was to analyze the nursing activities related to continuous renal replacement therapy (CRRT) in the intensive care units (ICU). Methods: We developed a list of 31 CRRT related nursing activities based on literature review and reviewed by expert group. A total of 109 direct time measurement records by 43 ICU nurses were collected and analyzed in terms of total time per shift, frequency, standard time, difficulty and performance levels of each CRRT nursing activity. Results: The mean time for CRRT nursing activity was 85.60 minutes per 8 hour shift. Nurses have spent average $9.46{\pm}6.98$ minutes in a shift for "waste fluid bag change" activity. In addition, "check catheter location" was the most time consuming single activity. The most difficult activity was "counseling-answer" and the most competent one was "dialysis solutions change". Conclusion: The CRRT nursing activities accounted for a significant portion of total nursing workload. Practical allocation of nursing staff for CRRT patient along with development of a new nursing cost system need to be considered. Continuous nursing educational and training programs on CRRT should be developed.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.69-77
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• 2020

PURPOSE: The aim of this study was to measure changes in spine inclination and thoracolumbar structure and morphology according to upper-extremity movements with and without resistance in order to evaluate the spine stability in workers. METHODS: Forty-eight middle-aged male workers (mean age, 40.48 ± 6.27 years) participated in this study. Using the spine analysis system, changes in the inclination of the spine and structure as well as shape of the thoracolumbar spine were measured. For posture measurement, the postures of standing, lifting the right and left arms (shoulder joint 90° flexion), and lifting with both arms were measured in random order. In addition, variables were measured using a resistance of 3 kg for each posture. The statistical significance level was set at α = .05 for all variables. RESULTS: There were statistically significant differences between the front and back inclinations of the spine, kyphotic curve of the thoracic spine, lordotic curve of the lumbar spine, rotation changes in the thoracolumbar spine, and rotation changes in the T4 vertebra (p < .05). However, there was no significant difference in the left and right tilts of the spine. In the post-hoc analysis, rotation changes in the T4 vertebra showed a significant difference in posture when resistance was applied to the left and right sides CONCLUSION: Causes of musculoskeletal diseases include excessive thoracic spine rotation, torsion, and hyperlordosis of the lumbar spine. Therefore, it is necessary to improve the working environment in order to ensure a healthy posture and prevent musculoskeletal diseases that can reduce the ability to carry various and/or excessive loads.

• Journal of Communications and Networks
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• v.12 no.1
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• pp.52-66
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• 2010

Since large objects consume substantial resources, web proxy caching incurs a fundamental trade-off between performance (i.e., hit-ratio and latency) and overhead (i.e., resource usage), in terms of caching and relaying large objects to users. This paper investigates how and to what extent the current dedicated-server based web proxy caching scheme is affected by large file transfers in a high bandwidth campus network environment. We use a series of trace-based performance analyses and profiling of various resource components in our experimental squid proxy cache server. Large file transfers often overwhelm our cache server. This causes a bottleneck in a web network, by saturating the network bandwidth of the cache server. Due to the requests for large objects, response times required for delivery of concurrently requested small objects increase, by a factor as high as a few million, in the worst cases. We argue that this cache bandwidth bottleneck problem is due to the fundamental limitations of the current centralized web proxy caching model that scales poorly when there are a limited amount of dedicated resources. This is a serious threat to the viability of the current web proxy caching model, particularly in a high bandwidth access network, since it leads to sporadic disconnections of the downstream access network from the global web network. We propose a peer-to-peer cooperative web caching scheme to address the cache bandwidth bottleneck problem. We show that it performs the task of caching and delivery of large objects in an efficient and cost-effective manner, without generating significant overheads for participating peers.

• Korean Journal of Community Nutrition
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• v.16 no.6
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• pp.751-761
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• 2011

The purpose of this study was to assess the physical activity level of Korean farmers to establish their estimated energy requirements during busy farming season. 113 farmers (mean age $51.9{\pm}7.2$ years, male 42, female 71) who own farmland area above 300 pyung participated in measurement of body weight and height and interviewing of one-day activity diaries. There was no significant difference in age, BMI between male and female. Obesity prevalence according to BMI among male and female farmers was 40.5% and 50.7% respectively. The farmers spent about 7 hours in sleeping and spent about 4 hours 35 minutes working on the farm and spent about 15 hours 30 minutes (64.6% of 24 hours) in "very light activities" and spent about 3 hours 31 minutes (14.7%) in "light activities". Physical activity level (PAL, activity coefficient) of male farmers was 2.63 which was significantly higher than that (2.19) of female farmers (p < 0.05). Estimated energy requirements (EER) for farmers who were different in age and gender were suggested. For example, the estimated energy requirements for male and female farmers were 3058 kcal/day and 2279 kcal/day, respectively. The results of this study suggest that estimated energy requirements (EER) of farmers should be differentiated according to seasonal workload and energy balance of farmers should be evaluated to prevent obesity.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.479-484
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• 2014

This paper presents the crew members fatigue survey in order to understand the current state of various fatigue causal factors and personnel fatigue subjective symptoms, and then analyzes the survey items. The results of this survey are as follows. Firstly, many crew members were struggling with the lack of sleep and rest hour. Secondly, environmental factors such as weather, ship motion and vibration, noise, accommodation condition etc. disturbed the sleep of crew members. In third, their duty hours were more than 10 hours per day in certain types of ship. In fourth, they felt fatigue a lot when they were on board because of the workload and stress. Lastly, in some measurement items of fatigue symptoms(physical, mental, emotional), many crew members were experiencing more than moderate fatigue symptoms.