• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.388-397
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• 2001

In forestry, where improvement of labor environment is quite impossible, improved posture would result in direct effects by preventing waste of physical strength, prevention of accidental injury caused by fatigue accumulated on certain body parts, and prevention of human error by inattentiveness due to weakened body. Therefore, this research carried on analysis of working posture in manual forest work(thinning using chain-saw, salvage cutting using chain-saw, clearing using hand saw, clearance of twiner using sickle, pruning using saw with a long handle, and tending of young growth using sickle) using OWAS analysis system. According to the OWAS method, percentage of OWAS action categories III and IV in the tasks using chain-saw and sickle was higher than another tasks. For the compared middle skillful worker group and low skillful worker group at felling work using chain-saw, percentage of OWAS action categories IV in middle skillful worker group was 5.1%, and low skillful worker group was 14.1%.

• Tunnel and Underground Space
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• v.23 no.3
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• pp.180-191
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• 2013

The purpose of this research was to find an optimal quarrying for marble by analyzing the applicability and the work efficiency of a chain saw machine newly introduced in the underground Baekwoon mine. From the test results of the physical properties of Baekwoon marble, which affects the efficiency of rock cutting, it was found to have similar physical characteristics as the ones which are now being produced in the other areas in Korea. And especially it shows isotropic property, which can be thought to be advantageous as a dimensional stone. To check the long-term quality of the marble as a stone material, several tests such as corrosion resistance test and abrasion test were carried out. It was found to be vulnerable to acid rain with decrease of weight and seismic wave velocity after applying artificial rain at pH 5.6 for 50 times. The percentage of wear from abrasion test was 22.67%. The working time and cutting speed of the chain saw machine were recorded and analyzed during the test-run at the quarry. The overall work cycle was assorted into 9 unit operations and the operating time per each unit was drawn. The operating times for the two cutting patterns, which could be possibly applicable to the work site, were compared. The results indicated that the pattern B, that the cutting sequence was set to minimize the movement of the machine, showed 6% less working hours than the pattern A, which first cuts the outer boundary. With cutting pattern analysis, the ore body in the Baekwoon mine was 3 dimensionally modeled and a quarrying plan considering the existing conditions of the marble was suggested.

• 월간산업보건
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• s.41
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• pp.21-32
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• 1991

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.344-355
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• 2012

This study was conducted to analyze on the operational time and productivities of logging operations in whole-tree logging operation system by tower-yarder and swing-yarder, and in cut-to-length logging operation system by excavator with grapple in order to establish the efficient logging operation system and to spread logging operation technique. In the analysis of operational time, in case of whole-tree logging operation system, the felling time was 46.6 sec/cycle by chain saw, the yarding time was 480.6 sec/cycle by tower-yarder, the yarding time was 287.4 sec/cycle by swing-yarder and the bucking time was 155.14 sec/cycle by chain saw. In case of the cut-to-length logging operation system, the felling and bucking time was 225.65 sec/cycle by chain saw, the cut-to-length extraction time was 4,972 sec/cycle by excavator with grapple, the branches and leaves extraction time was 3,143 sec/cycle by excavator with grapple. The forwarding time was 4,688 sec/cycle by wheel type mini-forwarder, the forwarding time was 2,118 sec/cycle by excavator with grapple and small forwarding vehicle. In the analysis of operational productivities, in case of whole-tree logging operation system, the average felling performance was $57.89m^3/day$ by chain saw, the average yarding performance was $20.3m^3/day$ by tower-yarder, $31.55m^3/day$ by swing-yarder respectively, the average bucking performance was $20.3m^3/day$ by chain saw. In case of the cut-to-length logging operation system, the average felling and bucking performance was $11.96m^3/day$ by chain saw, the average cut-to-length extraction performance was $34.75m^3/day$ by excavator with grapple, the average branches and leaves extraction performance was $37.66m^3/day$ by excavator with grapple, the average length of operation road construction was 73.8 m/day by excavator with grapple. The average forwarding performance by wheel type mini-forwarder and the average forwarding performance by excavator with grapple and small forwarding vehicle was $15.73m^3/day$ and $65.03m^3/day$, respectively.

• Archives of Plastic Surgery
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• v.46 no.1
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• pp.63-68
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• 2019

Background Hand injuries caused by chain saws, electric saws, and hand grinders range from simple lacerations to tendon injuries, fractures, and even amputations. This study aimed to understand the distribution of various types of hand and upper extremity injuries caused by power tools, in order to help prevent them, by investigating the incidence and cause of power tool injuries treated over a 4-year period at a single institution in Korea. Methods We reviewed the medical records of patients who visited a single institution for power tool-induced injuries from 2011 to 2014. The distribution of sex, age, injured body part, type of injury, and mechanism of injury sustained by patients who received hand and upper extremity injuries from using an engine saw, electric saw, or hand grinder was evaluated. Results Among 594 subjects who were injured by power tools, 261 cases were hand and upper extremity injuries. The average age was 53.2 years. Tendon injury was the most common type of injury. An electric saw was the most common type of power tool used. More injuries occurred in non-occupational settings than in occupational settings. Conclusions In this study, power tool-induced hand and upper extremity injuries were mostly caused by direct contact with electric saw blades. More injuries occurred due to non-occupational use of these tools, but the ratios of amputations and structural injuries were similar in the non-occupational and occupational groups.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.121-130
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• 1998

This study was carried out to investigate working time, productivity, and heart rate during thinning using chain saw in Japanese larch(Larix leptolepis) plantation site for analysis of physical work load, and to investigate maximal oxygen uptake of worker for analysis of maximal work capacity. The real working time was 366 minutes in a day ; about 192 minutes in the a.m., 174 minutes in the p.m.. The ratio of real working time per total working time was approximately 90%. The rate of moving(Mo) to real working times was 26.3, which was the largest one of work elements. Average maximal oxygen uptake, as an asset of personnel performance, was $2.42{\ell}/min$($46.5m{\ell}/kg/min$). During the real working time, average productivity, the mean rate of increase of heart rate, and the mean work load index was $2.62m^3/hr$, 93.2%, and 41.9%, respectively.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.229-238
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• 2013

This study was conducted to analyze on the operational cost of logging operations in the whole-tree logging operation system by tower-yarder and swing-yarder, and in the cut-to-length logging operation system by excavator with grapple in order to spread efficient logging operation technique and to establish the logging operation system. In the results of the analysis of operation cost, in case of the whole-tree logging operation system, the operation cost was 2,099 won/$m^3$ in felling by chain saw, 28,286 won/$m^3$ in yarding by tower-yarder, 18,265 won/$m^3$ in yarding by swing-yarder, 18,939 won/$m^3$ in bucking by excavator with grapple and chain saw, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle. In case of the cut-to-length logging operation system, the operation cost was 10,160 won/$m^3$ in felling and bucking by chain saw, 7,567 won/$m^3$ in cut-to-length extraction by excavator with grapple, 6,982 won/$m^3$ in branches and leaves extraction by excavator with grapple, 3,040 won/$m^3$ in the operation road construction by excavator with grapple, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle.

• Safety and Health at Work
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• v.12 no.1
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• pp.133-135
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• 2021

The COVID-19 pandemic has resulted in movement restrictions being instituted globally and the cessation of work at many workplaces. However, during this period, essential services such as healthcare, law enforcement, and critical production and supply chain operations have been required to continue to function. In Singapore, measures were put in place to protect the workers from infection at the workplace, as well as to preserve the operational capability of the essential service in a COVID-19 pandemic environment. This paper critically analyses the measures that were implemented and discusses the extension to broader general industry.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.583-592
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• 2014

This study was carried out to investigate the operational time and productivity of logging operation by chain saw, yarder attached on tractor, tower-yarder, mini-truck, mini-forwarder, and chipping operations by mini-chipper, large-chipper in order to develop the efficient logging operation system for utilization of forest-biomass. As a result, the average felling and bucking time using chain saw at the site 1 and 2 was observed to be 182.7 sec/cycle and 518.5 sec/cycle respectively. The average yarding time was 202.5 sec/cycle using yarder attached on tractor and 295.1 sec/cycle using tower-yarder. The average forwarding time was 2,073 sec/cycle using mini-truck and 2,248.4 sec/cycle using mini-forwarder. The operational time of felling and bucking using chain-saw can be delayed according to the direction of fallen trees. The selection of felling direction is very important to yarding operation because the direction between width-yarding and felling are interrelated. Productivity can be improved through educating and training operators in the yarding operations. Mini-forwarder is needed to use because of higher productivity and lower cost than mini-truck. The operational productivity of felling and bucking by chain saw was $66.96m^3/man{\cdot}day$ and $43.86m^3/man{\cdot}day$ at site 1 and 2 respectively. The yarding productivity was $5.68m^3/man{\cdot}day$ by yarder attached on tractor, $10.74m^3/man{\cdot}day$ by tower-yarder. The forwarding productivity was $21.29m^3/man{\cdot}day$ by mini-truck, $28.57m^3/man{\cdot}day$ by mini-forwarder. The chipping productivity was $4.42m^3/man{\cdot}day$ by mini-chipper, $21.87m^3/man{\cdot}day$ by large-chipper.

• Journal of Forest and Environmental Science
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• v.24 no.1
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• pp.47-51
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• 2008

The first pruning works of planted trees on forest area carry out when tree height reached at 6 meters. And the second works carry out when it grow to 12~13 meters of tree height. Pruning works are necessary for producing straight log without knar by tool or machine. Generally, the mechanized pruning works Self-propelled pruning machine, chain pruning saw and other tools are used in mechanized pruning works. However, manual pruning saw which is usually using pruning tool was for this study. To investigate the pruning works efficiency, Pinus densiflora, Pinus koraiensis and Pinus rigida which were distributed in Kangwon-Do was surveyed. Height of surveyed the trees were 10~16 meters and its pruning works range were 6.2~6.7 meters of tree height. As results, pruning works efficiency of Pinus densiflora, Pinus koraiensis and Pinus rigida were 3.14 min/tree, 5.06 min/tree and 4.44 min/tree, respectively. Also, possible pruning works of man-day for Pinus densiflora, Pinus koraiensis and Pinus rigida was 104, 64, and 81 trees, respectively.