• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.75-83
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• 2016

An experimental study on a subsea installation using an offshore crane was conducted. Concrete blocks, suction piles, and manifolds were considered in this study. Free decay tests were conducted to investigate the fluid characteristics of the subsea structures. The added masses of the structures were estimated. The motion response amplitudes of the subsea structures were compared for different structures and water depths. In addition, the dynamic tension transfer function of the crane wire was investigated. The root mean square values of the heave motion and the dynamic amplification factor of the wire tension were investigated in irregular waves.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.125-132
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• 2008

As of 2003, construction waste has been produced at the level of 130,614.8 tons/day, in which the amount of waste concrete was 92,639.1 tons/day and accounted for about 66.4% of the amount of construction waste. Waste concrete is mainly produced in construction work and civil engineering work. Especially, road surface crushing method using a large amount of water requires thorough management of concrete wastewater. The aim of this study was to analyze water pollution due to concrete wastewater generated in repair of bridge deck using road surface crushing equipment and to suggest reasonable countermeasures for solve the problem. In this study, it was surveyed current conditions of produced concrete wastewater in bridge deck repair, analyzed physical features of concrete wastewater, expected effects of water pollution on inflow rivers if it is not treated, established treatment plan of water pollution by categories, and calculated capacity of each treatment process and required amount of necessary chemicals. As a result of sampling wastewater generated in field sites and testing it at a lab scale, it was revealed that the original wastewater was produced in removing concrete from bridge deck slabs using surface crushing equipment whose pH was 12.53, CODMn was 12.910mg/L, SS was 547.0mg/L, and other heavy metals were included in extremely small quantities.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.503-507
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• 2011

Objective: This paper presents the factors influencing the effectiveness of materials handling equipments in agriculture. Background: Agriculture is one of the job categories where work-related musculoskeletal disorders(MSDs) are the most common. Statistics shows that majority of farm workers is exposed to repetitive and forceful body movements, lifting, lowering, pushing, pulling, or carrying heavy materials. In such a working environment, materials handling equipments are required and introduced to assist in the prevention of MSDs and other farm injuries. Method: Examples of materials handling equipments are rail carts, portable lifts, and bale handlers. Contributing factors influencing the effectiveness of materials handling equipments supplied in agriculture were identified based on the lessons learned from previous government-funded ergonomic projects. Results: Contributing factors identified include: (1) forward-looking attitude for the standardization of farming, its environments, and handling equipments, (2) participation of farm members in the process and evaluation of project, (3) leadership of project manager, (4) reinforcement of safety education and training, and (5) project selection and priority of handling equipment. Conclusion: Government-funded research planners, farmers, ergonomists, and farm machine experts are recommended to consider the factors identified when implementing materials handling equipments in agriculture. Application: Actual or potential application of this research includes recommendation for the effective implementation of material materials handling equipments in agricultural sectors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.346-349
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• 2015

Generally, in order to verify the degree of tire wear or abnormal wear, a driver or an auto mechanic checks the degree of tire wear and the existence of tire abnormality, directly with the naked eye or by way of using a gauge equipment. In case of such verification, individual subjective judgments may be involved or a driver may suffer heavy burdens to expend the time and cost for using the wheel alignment equipment. Therefore, this thesis will use a number of laser sensors to check the existence of abnormal wear and the degree of wear on each tire and develop a system checking the sides of tires to receive the tire information, so that subjective judgments may be overcome and objective and accurate judgments may be rendered.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.64-72
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• 2001

According to the regulation of IMO, oil discharge from ships is allowed under 15ppm only and an oil filtering equipment is essential. However, for large ships using heavy fuel oil of over S.G 0.98 and viscosity 380cSt and system oil, it has been in difficulty to process with existing filtering type of oily water separator. A parallel plate type oily water separator which is one of gravity type separators can be used as an assistant equipment for the oil filtering system to meet the present IMO standard of 15 ppm, because it is an efficient method in dealing with a large amount of rich oil with high specific gravity. This work is focused on the fundamental investigation of the performance of the plate type oily water separator by visualization method and PIV(Particle Image Velocimetry) measurement to acquire multi-point velocity data simultaneously. The experimental results showed that the space of the plates acts a significant role in separating process and it was found that an important point to minimize a vortex flow is to flow a large amount of fluid in space of the plates in order to promote the efficiency of separation.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.23-34
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• 2011

Recently, carelessness on safety management in construction sites has caused a sharper upward trend in accidents and disasters, compared to the past. Therefore, this study analyzes the causes of accidents that occurred on construction sites in the year of 2010, and proposes preventive measures. The construction industry had a heavy death rate with 279 out of 418 deaths from falls in all industrial sites, accounting for 66.7%. And the causation analysis found a particularly high incidence of temporary structure-related accidents, with falling off scaffolding as the most common cause of accidents. According to the causation analysis of fall-down accident cases, accidents induced by protrusion on construction sites are a big contributor resulting in the deaths of 312, accounting for 74.8%, which is deemed to be due to site disorderliness. And to remove floor protrusions and to secure workers' traffic line and safety, neat and thorough site arrangement is necessary. Against collision, efforts must be made to prevent equipment-pedestrian crashes on site, which necessarily requires emergency lamps, alarm bells, and safety poles and blocks to be installed, lighting systems to be improved, obstacles to be removed, site supervisors to be assigned to construction equipment works, and workers to be more intensely trained and supervised.

• The KSFM Journal of Fluid Machinery
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• v.12 no.6
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• pp.13-17
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• 2009

Ejector is an equipment devised for making use of the low pressure occurring from the fast fluid injection and it is a transportation equipment which can obtain vacuum using the kinetic energy of the fluid. This ejector system is, nowadays, widely used for construction machinery, heavy equipments, the cooling and ventilation of electronic devices and for the various fluid transportation and pumps. In this study, it is attempted to perform a numerical analysis and an experiment to find out the characteristics of fluid quantity, velocity and the pressure distribution of the induction pipe by changing the length and the radius ratio of the nozzle of ejector. From the results, it is investigated that the distributions of velocity and pressure of induction pipe attached are changing with the length and the radius ratio of the nozzle. In addition, it is shown that for the small and large ejector, the efficiency is the maximum when the length of the nozzle arrived to the neck of the ejector, however, if it is installed at below or above the neck the efficiency is rather decreased.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.7-13
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• 2012

Recently, carelessness on safety management in construction sites has caused a sharper upward trend in accidents and disasters, compared to the past. Therefore, this study analyzes the causes of accidents that occurred on construction sites in the year of 2007, and proposes preventive measures. The construction industry had a heavy death rate with 279 out of 418 deaths from falls in all industrial sites, accounting for 66.7%. And the causation analysis found a particularly high incidence of temporary structure-related accidents, with falling off scaffolding as the most common cause of accidents. According to the causation analysis of fall-down accident cases, accidents induced by protrusion on construction sites are a big contributor resulting in the deaths of 312, accounting for 74.8%, which is deemed to be due to site disorderliness. And to remove floor protrusions and to secure workers' traffic line and safety, neat and thorough site arrangement is necessary. Against collision, efforts must be made to prevent equipment-pedestrian crashes on site, which necessarily requires emergency lamps, alarm bells, and safety poles and blocks to be installed, lighting systems to be improved, obstacles to be removed, site supervisors to be assigned to construction equipment works, and workers to be more intensely trained and supervised.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3064-3066
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• 1999

The existing equipment with wire communication can expect the stability of data transmission. However, according to increasing a number of DTE (Data Terminal Equipment), wiring work becomes a heavy burden. Restriction to application about portable DTE and the lack of flexibility are another drawback of wire communication. This paper presents the design and implementation of a RF (Radio Frequency) based wireless communication system. The RF based module is designed to the multi communication between DTEs. The RF based module consists of RF circuit and microprocessor. The main properties of RF circuit are maximum 5Kbps transmission rate, maximum 90m transmission distance and 433MHz frequency band. The microprocessor rearrange the data into AHDLC(Advanced High level Data Link Control) format and then instructs RF circuits to transmit/receive the data. The RF module have a wide application field such as fire/security alarm, remote control/measurement etc..

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.11
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• pp.856-863
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• 2002

Seismic qualification of the main control board(MCB) for the nuclear power plant Ulchin 5 and 6 has been performed with the guideline of ASME Section III and IEEE 344 code. As the size and weight of the MCB are too large and heavy to excite using the excitation table, finite element analysis is used in order to investigate the dynamic behaviors and structural integrity of the MCB. As the fundamental frequencies of the equipment are found to be less than 33 Hz, which is the upper frequency limit for the dynamic analysis, response spectrum analysis using ANSYS is performed in order to combine the modal stresses within the frequency limit. In order to confirm the electrical stability of the major components of the MCB. modal analysis theory has been adopted to derive the required response spectra at the component locations. As the all combined stresses obtained from the above procedures are less than the allowable stresses and no mechanical or electrical failures are found from the seismic testing, the authors can confirm the safety of the nuclear equipment MCB under the given seismic loading conditions.