• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.299-305
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• 2014

In a ship-building, a transporter is the moving equipment to transport ship blocks from a workshop to another in a shipyard. The efficient scheduling of transporters has an important role for the operation of a building ship to be completed on schedule. There are the previous studies on the transporter scheduling for moving blocks in a shipyard. These studies have no consideration for the transporter combination to increase the productivity of moving blocks. This paper presents an efficient transporter scheduling model considering transporter combination explicitly. The objective of this model is to minimize the operational cost and maintain the workload balance among transporters. we also present three heuristics algorithms based on tabu search for finding the solution of the model. The efficiency of the proposed heuristics are verified with several computational tests.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.2952-2971
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• 2016

Outsourcing jobs to a public cloud is a cost-effective way to address the problem of satisfying the peak resource demand when the local cloud has insufficient resources. In this paper, we studied the management of deadline-constrained bag-of-tasks jobs on hybrid clouds. We presented a binary nonlinear programming (BNP) problem to model the hybrid cloud management which minimizes rent cost from the public cloud while completes the jobs within their respective deadlines. To solve this BNP problem in polynomial time, we proposed a heuristic algorithm. The main idea is assigning the task closest to its deadline to current core until the core cannot finish any task within its deadline. When there is no available core, the algorithm adds an available physical machine (PM) with most capacity or rents a new virtual machine (VM) with highest cost-performance ratio. As there may be a workload imbalance between/among cores on a PM/VM after task assigning, we propose a task reassigning algorithm to balance them. Extensive experimental results show that our heuristic algorithm saves 16.2%-76% rent cost and improves 47.3%-182.8% resource utilizations satisfying deadline constraints, compared with first fit decreasing algorithm, and that our task reassigning algorithm improves the makespan of tasks up to 47.6%.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.1-14
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• 2006

Sort-last parallel rendering using a cluster of GPUs has been widely used as an efficient method for visualizing large- scale volume datasets. The performance of this method is constrained by load balancing when data parallelism is included. In previous works static partitioning could lead to self-balance when only task level parallelism is included. In this paper, we present a load balancing scheme that adapts to the characteristic of volume dataset when data parallelism is also employed. We effectively combine the hierarchical data structures (octree and BSP tree) in order to skip empty regions and distribute workload to corresponding rendering nodes. Moreover, we also exploit a 3D clustering method to determine visibility order and save the AGP bandwidths on each rendering node. Experimental results show that our scheme can achieve significant performance gains compared with traditional static load distribution schemes.

• Journal of the Korea Society for Simulation
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• v.22 no.1
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• pp.77-86
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• 2013

Cloud computing is one of the distributed computing environments and utilizes several computing resources. Cloud environment uses a virtual machine to process a requested job. To balance a workload and process a job rapidly, cloud environment uses a provisioning technique and assigns a task with a status of virtual machine. However, a scheduling method for cloud computing requires a definition of virtual machine availabilities, which have an obscure meaning. In this paper, we propose Fuzzy logic driven Virtual machine Provisioning scheduling using Resource Evaluation(FVPRE). FVPRE analyzes a state of every virtual machine and actualizes a value of resource availability. Thus FVPRE provides an efficient provisioning scheduling with a precise evaluation of resource availability. FVPRE shows a high throughput and utilization for job processing on cloud environments.

• 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 Information Processing Systems
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• v.8 no.4
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• pp.603-620
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• 2012

Proxy Mobile IPv6 (PMIPv6) is a network-based mobility support protocol and it does not require Mobile Nodes (MNs) to be involved in the mobility support signaling. In the case when multiple interfaces are active in an MN simultaneously, each data flow can be dynamically allocated to and redirected between different access networks to adapt to the dynamically changing network status and to balance the workload. Such a flow redistribution control is called "flow mobility". In the existing PMIPv6-based flow mobility support, although the MN's logical interface can solve the well-known problems of flow mobility in a heterogeneous network, some missing procedures, such as an MN-derived flow handover, make PMIPv6-based flow mobility incomplete. In this paper, an enhanced flow mobility support is proposed for actualizing the flow mobility support in PMIPv6. The proposed scheme is also based on the MN's logical interface, which hides the physical interfaces from the network layer and above. As new functional modules, the flow interface manager is placed at the MN's logical interface and the flow binding manager in the Local Mobility Anchor (LMA) is paired with the MN's flow interface manager. They manage the flow bindings, and select the proper access technology to send packets. In this paper, we provide the complete flow mobility procedures which begin with the following three different triggering cases: the MN's new connection/disconnection, the LMA's decision, and the MN's request. Simulation using the ns-3 network simulator is performed to verify the proposed procedures and we show the network throughput variation caused by the network offload using the proposed procedures.

• Journal of the Korea Society for Simulation
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• v.29 no.1
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• pp.57-69
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• 2020

Many researchers have recommended that DBR scheduling would be an efficient method to maintain the balance of their workload among many processes in the general flow shop. However, as product variety has increased in recent years, the process has become more complex and requires the re-entrance of raw materials and work in process. The re-entrant line has known for the complex manufacturing process that raw materials are repeatedly processed on the same machine. This study reviews the applicability of DBR against the re-entrant manufacturing line due to the distinguishing characteristics and the higher complexity caused by multiple visits of a job into the identical process. In order to apply the DBR method to the re-entrant process, the main idea is to reconstruct re-entrant process into a virtual flow process(loop) that has a single bottleneck. This study discusses the following two questions. First, DBR is also superior to traditional scheduling methods against re-entrant manufacturing line. And how we structure and detect the system bottleneck (or sub-bottleneck) through drum-buffer-rope concepts. To answer the above questions, we experimented and analyzed the effects of the applicability of DBR under the general re-entrant process model(TRC, Technology Research Center). As a result, we have identified a balance between loops for cycle time and work in process.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.126-135
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• 2007

This study was conducted to identify the effects of the oriental medicine Qigong Exercise on the brain power, HRV, pulsation, live blood condition among young boys and girls. The study was performed with two group(control group and experimental group) in a pre-test/post-test design. The subjects were 44 young boys and girls selected by a some middle school in Busan. The oriental medicine Qigong Exercise program consists of 80-minute sessions three times a week over 5 months. All of the subjects were examined on the congnition assessment tool, stress assessment tool, oriental medicine pulsation 3-D MAC, live blood condition analyzer Prior and post surveys were measured before and after the experiment. In the cognition assessment, the amplitude of ERS were increased afer Qigong Exercise. The Success and the Concentration were significantly increased afer Qigong Exercise, the Error was significantly decreased afer Qigong Exercise. The Cognition strength was significantly increased, but the Reponse time was not significantly decreased afer Qigong Exercise. And the Workload was not significantly decreased, the Total Score was not significantly increased afer Qigong Exercise. Among the stress assessment, RRV tachogram's ‘mean RR’ was significantly increased, ‘mean HRV’ was significantly decreased afer Qigong Exercise. SDNN was not significantly increased, Complexity was not significantly increased afer Qigong Exercise. And TP(RRV power's total power) was not significantly increased, VLF and HF was significantly increased, and LF was significantly decreased afer Qigong Exercise. ANS's norm LF was not significantly decreased, but norm HF was significantly increased afer Qigong Exercise. In the RRV's Phase Plot, RMSSD and SDSD were not significantly increased, pnn50 was not significantly decreased afer Qigong Exercise. On the whole, Parasympathetic Activity and Stress Endurance were significantly increased, but Cardiac Activity and Physical Arousal were not significantly increased afer Qigong Exercise. Cardiac Aging was not significantly decreased afer Qigong Exercise. Sympathetic Activity, Autonomic Nervous System Balance and Heart-load were not significantly decreased afer Qigong Exercise. In the pulsation, press power was increased(15%), and w/t(pressurization time / pulsation time) was decreased(20%) afer Oigong Exercise. And the live blood condition was not changed afer Qigong Exercise. As mentioned above; the oriental medicine Qigong Exercise program was identified the effects of the inspiration of the brain power, heart rate and anti-stress.

• The KIPS Transactions:PartD
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• v.10D no.7
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• pp.1067-1076
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• 2003

Database sharing system (DSS) refers to a system for high performance transaction processing. In DSS, the processing nodes are locally coupled via a high speed network and share a common database at the disk level. Each node has a local memory and a separate copy of operating system. To reduce the number of disk accesses, the node caches database pages in its local memory buffer. In this paper, we propose a dynamic transaction routing algorithm to balance the load of each node in the DSS. The proposed algorithm is novel in the sense that it can support node-specific locality of reference by utilizing the primary copy authority assigned to each node; hence, it can achieve better cache hit ratios and thus fewer disk I/Os. Furthermore, the proposed algorithm avoids a specific node being overloaded by considering the current workload of each node. To evaluate the performance of the proposed algorithm, we develop a simulation model of the DSS, and then analyze the simulation results. The results show that the proposed algorithm outperforms the existing algorithms in the transaction processing rate. Especially the proposed algorithm shows better performance when the number of concurrently executed transactions is high and the data page access patterns of the transactions are not equally distributed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.664-675
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• 2016

The purpose of the study was to explore the nurses' perception of flexible working and present an operational guideline for implementation. The data were collected from a survey of 532 nurses conducted from 10 February to 24 February, 2015, using simple random sampling. SPSS 21.0 was used to analyze the data. This study found that the demanding for shorter hour shifts was highest ($M=3.89{\pm}0.87$) and 242 participants (46.2%) intended to apply the shift, followed by a fixed night shift, fixed weekend shift, and 12 hour shift. The common reasons identified were the poor environment of shift work and the challenges of child care. The increased time for personal development, relaxation activity to improve the quality of life and child care was highlighted and work-life balance was noted as a positive impact of flexible working. The negative impacts of flexible working were being likely to become temporary workers. These results can help establish uniform working conditions of nurses in the future by providing a standardized operational guideline as a precondition for reasonable compensation and working environment according to a flexible working pattern.