• Journal of Construction Engineering and Project Management
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• v.2 no.2
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• pp.18-27
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• 2012

Despite the rapid development in the construction industry due to the changing new technologies, many projects still fail to meet target deadlines. Shortage in manpower and skilled laborers is one of the main reasons for such delays. Markets with high economic growth and economic expansion (such as Gulf Countries in the Middle East) may have pronounced labor the shortages. Labor subcontracting practices are used sometimes to increase production rates and meet project deadlines. This paper explains and analyses labor subcontracting practices currently being used in many places around the world (and especially in the Gulf Countries) and in particular defines a maximum overtime rate for laborers in the laborer-subcontracting method ensuring that the contractor gains both the time saved during overtime and also reduces the cost per unit produced. The mathematical model used formalizes a closed-form equation for overtime pay in similar situations and as such can be applicable worldwide. Data was collected from representative projects that employed such practices from various trades. Validation of the model and formula has been tested successfully by analyzing historic data. The results prove that contractors often do not reach the optimum use of their practices resulting in a higher cost per unit. The presented model and the analysis should be of interest to many contractors currently involved in the practice or considering its use and to those who wish to find new methods that would help in eliminating as much wastes as possible by allocating their resources in the most efficient way.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.9
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• pp.189-196
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• 2020

Recently, GPU cloud computing technology applying GPU(Graphics Processing Unit) devices to virtual machines is widely used in the cloud environment. In a cloud environment, GPU devices assigned to virtual machines can perform operations faster than CPUs through massively parallel processing, which can provide many benefits when operating high-performance computing services in a variety of fields in a cloud environment. In a cloud environment, a GPU device can help improve the performance of a virtual machine, but the virtual machine scheduler, which is based on the CPU usage time of a virtual machine, does not take into account GPU device usage time, affecting the performance of other virtual machines. In this paper, we test and analyze the performance degradation of other virtual machines due to the virtual machine that performs GPGPU(General-Purpose computing on Graphics Processing Units) task in the direct path based GPU virtualization environment, which is often used when assigning GPUs to virtual machines in cloud environments. Then to solve this problem, we propose a GPGPU task management method for a virtual machine.

• Korean Journal of Construction Engineering and Management
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• v.20 no.2
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• pp.95-104
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• 2019

EPC plant projects are large and complex, requiring systematic working methodologies, accumulated data, and thorough planning through communications between the entities. In this study, the method of extracting the process planning information using asset data of the plant project and using it to present the initial process plan is presented through the concept of IAP(Interactive Planning). In order to carry out the effective IAP at the early stage of the project, this study extracted the schedule element information from the asset data, created the process plan for each work package, and applied it to the sample project case. Through the proposed IAP methodology, it is possible to promote the utilization of asset data, to identify schedule risks, and to develop countermeasures, which can form the basis for establishing the process management strategy to successfully complete the project.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.3-13
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• 2010

Differential Fault Analysis (DFA) is widely known for one of the most efficient method analyzing block cipher. In this paper, we propose a new type of DFA on DES (Data Encryption Standard). DFA on DES was first introduced by Biham and Shamir, then Rivain recently introduced DFA on DES middle rounds (9-12 round). However previous attacks on DES can only be applied to the encryption process. Meanwhile, we first propose the DFA on DES key-schedule. In this paper, we proposed a more efficient DFA on DES key schedule with random fault. The proposed DFA method retrieves the key using a more practical fault model and requires fewer faults than the previous DFA on DES.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.405-430
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• 2021

Production planning is a key part of production management of manufacturing enterprises. Since computerization began, modern production planning has been developed starting with Material Requirement Planning (MRP), and today Enterprise Resource Planning (ERP), Advanced Planning and Scheduling (APS), Supply Chain Management (SCM) has been spreading and advanced. However, in the shipbuilding field, rather than applying these general-purpose production planning methodologies, in most cases, each shipyard has developed its own production planning system. This is because the applications of general-purpose production planning methods are limited due to the order-taking industry such as shipbuilding with highly complicated construction process consisting of millions of parts per ship. This study introduces the design and development of the production planning system reflecting the production environment of heavy shipyards in Korea. Since Korean shipyards such as Hyundai, Daewoo and Samsung build more than 10 ships per year (50-70 ships in the case of large shipyards), a planning system for the mixed production with complex construction processes is required. This study draws requirements using PI/BPR (process innovation and business process reengineering) methodology to develop a production planning system for shipyards that simultaneously build several ships. Then, CBD software development methodology was applied for the design and implementation of planning system with drawn requirements. It is expected that the systematic development procedure as well as the requirements and functional elements for the development of the shipyard production planning system introduced in this study will be able to present important guidelines in the related research field of shipbuilding management.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.3-14
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• 2022

Quantitative analysis of the number of construction workers and construction period can present a new standard for appropriate personnel. This study presents a Queueing model that predicts the execution time of work procedures, the most important factor among work efficiency indicators. During the working cycle of apartment frame construction the same process tends to be repeated the volume of contruction. Based on these characteristics, this study used a Queueing Model and analyzed reference layer cycle of the delayed frame construction. After adjusting the number of people and the construction period, the performance of the model was analyzed and suggested. This study aims to support the decision making of personnel distribution according to the volume of construction by performing a performance analysis of the Queueing Model.

• The Korean Journal of Archival Studies
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• no.20
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• pp.77-114
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• 2009

The actual conditions of the labor unions are primitive. First, there is no good records management regulation. At this research, I found it that most regulations of the labor unions were all the same. I think they have been copied a kind of one of originality. Second, the definition of records were very narrow, like documentary evidence. Third, the classification, filing, disposal regulations are the below level of the public institution in 1970s. Fourth, there are no standards of the records scheduling for the labor records. What kind of labor records have the historical values? I could not find, only the documentary evidence value. So, I think The actual conditions of the labor unions are primitive. I investigated the collections of the Southern Labor Archives in USA. There were many kind of records. For example, the records of regional labor unions also central labor unions, pamphlets, journals, photos, personal records, oral history, organizational records like protocols article of associations internal rules, minute books etc. Like this the collections of the Southern Labor Archives in USA are very various. But our actual conditions of the labor unions is far from that. Rather, we just have tried collected records for publishing the white papers. But this habitual practice would not be desirable. Because they must manage the records from the producing time. Mostly, 'laborer history HANNAE' were organised, and they are trying the collecting and management of the labor records. Also They are trying the computerizing, compilation. 'HANNAE' has the condition for the transformation of the labor archives. But if they want to be really, they must make the records management infra and so, should normalize the record management firstly. For example, They must be keep the standardized records management regulations, records scheduling redesigned. the developing standard model for the records management. And they have the vision for the hub of the labor archives. When coming to this, it will be realized the labor archives Now the records for the working class are disappearing. The managing the records for the labor is another labor movement. All together should join it. But I think the supporting of the archival science research colleagues will be the essential part.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.3
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• pp.1-13
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• 2020

The management of agricultural water can be divided into management of agricultural infrastructure and operation to determine the timing and quantity of water supply. The target of water management is classified as water-supply facilities, such as reservoirs, irrigation water supply, sluice gate control, and farmland. In the case of agricultural drought, there is a need for water supply capacity in reservoirs and for drought assessment in paddy fields that receive water from reservoirs. Therefore, it is necessary to analyze the water supply amount from intake capacity to irrigation canal network. The analysis of the irrigation canal network should be considered for efficient operation and planning concerning optimized irrigation and water allocation. In this study, we applied a hydraulic analysis model for agricultural irrigation networks by adding the functions of irrigation canal network analysis using the SWMM (Storm Water Management Model) module and actual irrigation water supply log data from May to August during 2015-2019 years in Sinsong reservoir. The irrigation satisfaction of ponding depth in paddy fields was analyzed through the ratio of the number of days the target ponding depth was reached for each fields. This hydraulic model can assist with accurate irrigation scheduling based on its simulation results. The results of evaluating the irrigation efficiency of water supply can be used for efficient water distribution and management during the drought events.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.108-117
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• 2013

The domestic CM business market has continued to grow, but its size is relatively small yet in comparison with the total size of the domestic construction industry. Evaluation of CM projects was conducted through questionnaire surveys. Both clients and CM firms showed positive satisfaction levels. Nevertheless, the clients' satisfaction levels were relatively low in safety management, cost management, and document and information management. Superior areas of CM tasks were time management and recovery scheduling, quality control and technical instruction, and design value engineering. On the other hand, inferior areas of CM tasks were claim analysis and dispute resolution, cost estimation, and life cycle costing. Both entities have agreed with the positive effects of CM involvement in terms of cost saving, time reduction, quality improvement, and safety incidents prevention to at least 0~5% extent.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.5
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• pp.253-260
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• 2014

European Space Agency has recognized Integrated Modular Avionics and ARINC specification 653 as avionics computer system for space application. Integrated Modular Avionics specification reduces the space by integrating a system composed of many electronic devices into a computer. recent researches have been studying how to apply the ARINC 653 into an open source operating system, such as Linux. These studies have concentrated on partition scheduling for time separation. However, requirements to guarantee spatial separation should be further analyzed to ensure deterministic execution time. Therefore, memory management is needed to verify spatial isolation on Linux systems. This research proposes a new method to accomplish spatial isolation for the ARINC 653 specification in Linux. We have added new data structures and system calls to handle functionalities for spatial separation. They are used during the partition startup process. The proposed method was evaluated on the LEON4 processor, which is the next generation microprocessor to be used in the future space missions. All implementations confirm that spatial isolation of the ARINC 653 specification was accomplished.