• Proceedings of the Safety Management and Science Conference
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• 2005.05a
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• pp.199-212
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• 2005

Many countries of the world is driving forward development of large-scale hub port. They are now pushing ahead with setting up of effective marketing strategies to survive in keen competitions of the 21st century port industry. The port is of ever increasing importance for the bridge connecting sea and road transportation in handling international cargoes. The port, differently from general working places, is a closed area required for security, customs, and quarantine procedures. The loading and unloading is being done differently by ports, cargoes, and ships. To do loading and unloading, a lot of equipment and different types of labor are required, which flow is complicated and safe management is essential. As above mentioned the port is very unique and very deteriorated working place in its working environment. The purpose of this study is to propose ways to reduce and prevent from port accidents. As first step to do this, we have collected 923 accidents happened at Incheon Port during the period of 1994 to 2003. We have thoroughly analyzed characteristics, harmfulness, and risk of the loading/unloading they have done, as well as the accident frequency and relationship between the accidents. As second step to further analyze, We have employed DMAIC technology, an advanced process of 6 sigma presently in spotlight as the best program for management innovation. This analysis results in recognition of important accident characteristics, causes and effects analysis, critical causes of accident, and suggestions to decrease accidents.

• Journal of the Korea Safety Management & Science
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• v.7 no.2
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• pp.13-27
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• 2005

Many countries of the world is driving forward development of large-scale hub port. They are now pushing ahead with setting up of effective marketing strategies to survive in keen competitions of the 21st century port industry. The port is of ever increasing importance for the bridge connecting sea and road transportation in handling international cargoes. The port, differently from general working places, is a closed area required for security, customs, and quarantine procedures. The loading and unloading is being done differently by ports, cargoes, and ships. To do loading and unloading, a lot of equipment and different types of labor are required, which flow is complicated and safe management is essential. As above mentioned the port is very unique and very deteriorated working place in its working environment. The purpose of this study is to propose ways to reduce and prevent from port accidents. As first step to do this, we have collected 923 accidents happened at Incheon Port during the period of 1994 to 2003. We have thoroughly analyzed characteristics, harmfulness, and risk of the loading/unloading they have done, as well as the accident frequency and relationship between the accidents. As second step to further analyze, We have employed DMAIC technology, an advanced process of 6 sigma presently in spotlight as the best program for management innovation. This analysis results in recognition of important accident characteristics, causes and effects analysis, critical causes of accident, and suggestions to decrease accidents.

• Journal of the Korea Safety Management & Science
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• v.13 no.4
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• pp.25-33
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• 2011

Workers in logistics centers also are exposed to serious musculoskeletal disorders the same as workers in general manufacturing due to operating forklifts and other labor duties. The frequency of these work related injuries decreases, workers' job satisfaction In addition, it causes many employees questioning a job change, which is regarded as the primary factor which drops the productivity. In this paper, we conducted a survey ti perceive the correlation between work related injuries in the fields of distribution centers and job satisfaction. Furthermore we made statistical analysis with our findings. The results of our analysis showed that the frequency of work related injuries due to workers' repetitive loading and unloading work is the primary factor which lowers job satisfaction. In order to improve aforementioned problem we propose first of all loading and unloading on pallet basis, second of all automation and computerization of logistics systems, and third of all ensurinf sufficient break time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.10
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• pp.672-678
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• 2010

The purpose of this study is to develop a stacking guidance system (SGS) of containers in the mobile harbor (MH). A mobile harbor is a floating structure especially designed for loading and unloading containers from and to a large container ship. A novel stacking guidance system was proposed for unloading the container in an effective way against possible vibrations of the floating body. The guidance system works as an aid for loading containers with a wider opening for easier stacking of a container into a moving storage cell due to waves. In order to determine the most effective inclination angle of the cell-guide, this study performed the dynamic analysis of the SGS equipped in the MH subject to fluctuations of the sea. The motions of the guidance system and a container loaded were calculated using ADAMS. The simulation results of the contact force between the two rigid bodies showed that a desirable angle of the cell-guide should be around 20 degrees from the vertical. This proposed SGS can considerably reduce the loading and unloading time, and will enhance the performance of the MH.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.65-75
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• 1998

The fracture resistance curve is one of most important and design techniques employed in nuclear pressure vessel structures. This study is to evaluate the J-R curve characteristics for the SA508C-3 by the unloading compliance method and load rato analysis. The effect of strain aging for the exponential correlation of the J-R curve in this metal are investigated at room temperature, 20$0^{\circ}C$ and 30$0^{\circ}C$. The load ratio analysis method can evaluate the J-R curve by using the simple tension load-displacement curve only without the repeat of the unloading and loading. Therefore, the analysis by the proposed load ratio method has a merit, in comparison with the unloading compliance method, which can measure the crack length without the precision measurement equipment.

• Transactions of Materials Processing
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• v.22 no.8
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• pp.470-476
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• 2013

The aim of the current study was to predict shape recovery behavior of Ni-Ti shape memory alloy (SMA) wire after loading-unloading and after wire drawing. The superelasticity of SMA was analyzed by a hyper-elastic model for the Mullins effect using ABAQUS. Firstly, tensile tests and loading-unloading tests of the Ni-Ti SMA wire with a diameter 1.0 mm were performed using an MTS servo-hydraulic tester. The parameters for the Mullins effect were computed by ABAQUS based on curve-fitting of the loading-unloading test data. The proposed FE-model predicted the shape recovery of Ni-Ti SMA after wire drawing. Finally, the effectiveness of the model was verified by drawing experiments. The wire drawing experiments using the Ni-Ti SMA were conducted on a drawing machine(1ton, 50mm/s). In order to evaluate the shape recovery of Ni-Ti SMA, the drawn wires are annealed for 30min at $450^{\circ}C$.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.262-267
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• 2004

The unloading compliance method is the most commonly used method to evaluate the fracture resistance characteristics of a material. In dynamic loading condition, the direct current potential drop(DCPD) method has been used because the unloading compliance method can not be applied due to the discontinuity of loading. However, even in the dynamic test using DCPD method, there is a problem that the voltage drops sharply on the initiation of crack. For the reason metioned above, the normalization method was suggested on ASTM E 1820 which is revised recently, as a new method to evaluate the dynamic fracture resistance characteristic. The nomalization method can be used to obtain a fracture resistance curve directly from a load-load line displacement. In this study, we obtained two fracture resistance curves from static test of welding part of nuclear piping both by unloading compliance and nomalization method. The two curves were almost same each other, so the adaptability of the nomalization method has been proved. We conducted a dynamic fracture resistance test for the same material. The fracture resistance curve from the dynamic test was obtained by normalization method and compared to that of the static test result.

• Geomechanics and Engineering
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• v.14 no.5
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• pp.459-466
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• 2018

By conducting uniaxial loading cycle tests on the coal rock with outburst proneness, the dilatation characteristics at different loading rates were investigated. Under uniaxial loading and unloading, the lateral deformation of coal rock increased obviously before failure, leading to coal dilatation. Moreover, the post-unloading recovery of the lateral deformation was rather small, suggesting the onset of an accelerated failure. As the loading rate increased further, the ratio of the stress at the dilatation critical point to peak-intensity increased gradually, and the pre-peak volumetric deformation decreased with more severe post-peak damage. Based on the laboratory test results, the lateral deformation of the coals at different depths in the #1302 isolated coal pillars, Yangcheng Coal Mine, was monitored using wall rock displacement meter. The field monitoring result indicates that the coal lateral displacement went through various distinct stages: the lateral displacement of the coals at the depth of 2-6 m went through an "initial increase-stabilize-step up-plateau" series. When the coal wall of the working face was 24-18 m away from the measuring point, the coals in this region entered the accelerated failure stage; as the working face continued advancing, the lateral displacement of the coals at the depth over 6 m increased steadily, i.e., the coals in this region were in the stable failure stage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.873-883
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• 2014

This study proposed an estimation method of allowable wave height for loading and unloading of the ship considering ship motion that is affected by ship sizes, mooring conditions, wave periods and directions. The method was examined validity by comparison with wave field data at pier $8^{th}$ in Pohang new harbor. The wave field data obtained with wave height of 0.10~0.75m and wave period of 7~13s in ship sizes of 800~35,000ton when a downtimes have occurred. On the other hand, the results of allowable wave height for loading and unloading of the ship in this method have obtained with wave heights of 0.19~0.50m and wave periods of 8~12s for ship sizes of 5,000, 10,000 and 30,000ton. Thus this method well reproduced the field data respond to various a ship sizes and wave periods. And the results of this method tended to decrease in 16~62% when have considered long wave, and it is decreased in 0~46% when didn't consider long wave than design standards in case of the ship sizes of 5,000~30,000ton, wave period of 12s and wave angle of $75^{\circ}C$. The allowable wave heights for loading and unloading of the ship proposed by design standards are didn't respond to various the ship sizes and wave periods, and we have found that the design standards has overestimated on smaller than 10,000ton.

• Journal of the Korean Society of Safety
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• v.6 no.4
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• pp.21-27
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• 1991

Acoustic Emission was monitored during tensile test and loading-holding-unloa-ding cycle test for two types (notched and unnotched) of CFRP specimens. AE activities showed that the fiber breakage during tensile tests depended upon the specimen geometry. We obtained new AE parameter such as the ration (damage ratio= AE events during unloading test / AE events during loading test) and the felicity ratio from which we investigated dynamic fracture process of CFRP specimens. The damage ratio of AE events was shown to be a good indicator to distinguish the generated fracture mechanism, such as fiber breakage and delamination. Also, ultrasonic testing results after loading-holding-unloading cycle test were good agreement with AE test results to detect defects or fiber breakage.