• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.438-443
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• 2020

To transfer files between nodes on network based on Ethernet, file transfer protocol (FTP) on TCP/IP and trivial file transfer protocol (TFTP) on UDP/IP are mostly used. Due to the lack of resources (processor, memory and so on) in the embedded system where we generally use for simple works with small firmware like ones; many of the systems implement only UDP/IP for their network stacks. Thus, TFTP is greatly to be preferred. For examples, environmental sensor devices for sensor networks, Boot Loader for general embedded device and preboot execution environment (PXE) boot for PC provide the TFTP. The logic of TFTP is simple for file transmission but, there is Stop-And-Wait problem during the process which occurs long blocking time. In this paper, we propose an algorithm which called QuTFTP(Quick UDP Trivial File Transfer Protocol) to reduce the length of the blocking time and to be compatible with the legacy TFTP.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.11-21
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• 2017

Artillery fire power due to effectiveness which is hard to predict well-planned and surprising attack can give a fear and shock to the personnel and is a very core weapon system and takes a critical role in wartime. Therefore in order to maximize operational effectiveness, Army required protecting artillery and takes a quick attack action through rapid construction of artillery's positions. The artillery use artillery's position to prevent exposure by moving to other position frequently. They have to move and construct at new artillery's positions quickly against exposing existed place by foe's recognition. These positions should be built by not manpower but engineering construction equipment. Because artillery positions have to protect human and artillery equipment well and build quickly. Military engineering battalion have lots of construction equipment which include excavator, loader, dozer, combat multi-purposed excavator, armored combat earthmover dump truck and so on. So they have to decide to optimal number of Team combining these equipments and determine construction sequence of artillery's position in operational plan. In this research, we propose to decide number of Team efficiently and allocate required construction's positions for each Team under constraints of limited equipments and time. To do so, we develop efficient heuristic method which can give near optimal solution and be applied to various situation including commander's intention, artillery position's priority or grouping etc. This heuristic can support quick and flexible construction plan of artillery positions not only for using various composition's equipment to organize Teams but also for changing quantity of positions.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.53-61
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• 2015

Development of highly efficient and energy-saving tractors has been one of the issues in agricultural machinery. For design of such tractors, measurement and analysis of load on major power transmission parts of the tractors are the most important pre-requisite tasks. Objective of this study was to perform pre-processing procedures before effective analysis of load data of agricultural tractors (30, 75, and 82 kW) during major field operations such as plow tillage, rotary tillage, baling, bale wrapping, and to select the suitable pre-processing method for the analysis. A load measurement systems, equipped in the tractors, were consisted of strain-gauge, encoder, hydraulic pressure, and radar speed sensors to measure torque and rotational speed levels of transmission input shaft, PTO shaft, and driving axle shafts, pressure of the hydraulic inlet line, and travel speed, respectively. The entire sensor data were collected at a 200-Hz rate. Plow tillage, rotary tillage, baling, wrapping, and loader operations were selected as major field operations of agricultural tractors. Same or different farm works and driving levels were set differently for each of the load measuring experiment. Before load data analysis, pre-processing procedures such as outlier removal, low-pass filtering, and data division were performed. Data beyond the scope of the measuring range of the sensors and the operating range of the power transmission parts were removed. Considering engine and PTO rotational speeds, frequency components greater than 90, 60, and 60 Hz cut off frequencies were low-pass filtered for plow tillage, rotary tillage, and baler operations, respectively. Measured load data were divided into five parts: driving, working, implement up, implement down, and turning. Results of the study would provide useful information for load characteristics of tractors on major field operations.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.657-666
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• 2006

The precast concrete beam-column connectors to retrofit an apartment building were investigated experimentally. Five precast concrete beam-column connectors were considered to develop a modified model which was adapted to domestic construction conditions from the DDC(dywidag ductile connection) of Germany. Special H-shape steel hardware was used to decrease the width of column and beams for the construction of external frames in apartments. It was found that the DDC had high joint strength and ductility, however failed in inclined shear crackings in the columns. The modified one showed better behaviors in tests because they did not show critical column crackings at failure. The test result of modified one with grouting was compared to that of the one without grouting within the duct. The one with grouting showed higher strength and ductility in failure than that without grouting.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.167-176
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• 2010

Managing the growing number of data generated through various processes requires the aid of Database Management System (DBMS) to efficiently handle the huge amount of data. These data can be inserted into database m real time or in batch, that come from multiple sources, including those that are coming from inside and outside of a network. The insertion of large amount of data is commonly done through specific bulk loading or insertion function supplied by each individual DBMS. In this paper, we analyze and evaluate on handling data bulk loading for heterogeneous systems that is organised as multi-tiered architecture and compare the result of DBMS bulk loader against program insertion from a software development perspective. We propose a hybrid solution using staging database that can be easily deployed for enhancing bulk loading performance compared to insertion by application.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.181-186
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• 2013

In recent years, eco-friendliness and high fuel economy have become important issues for commercial tractors. Electric tractors are often required for operation in a greenhouse. However, the battery capacity limits the available operation time. To overcome this problem, a plug-in hybrid electric tractor is considered a reasonable alternative. This tractor has a basic driving ability and can operate in various working modes such as mower, rotary, loader, and trailing. This study focuses on the energy management strategy by considering various working modes.

• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.97-104
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• 1998

In order to advise how to solve the problems and suggest on the mechanization of beef farm, the facilities and equipment for feeding and supplying water to the animals and transporting manure, and farm machineries of sixty-seven beef cattle farms in western Chungnam Province were surveyed. The results are as follows; 1. The proportions of number of heads per farm for above 70, 50∼70, 30∼50, 10∼30 and below 10 heads were 26, 18, 29, 13 and 13, respectively. The farms with the annual income more than 30 million won are consisted of 67.6% of the farms surveyed which showed to be higher than national average. 2. Only 19% of farms had automatic feeding system. Water was supplied by water cup(45%), opening and shutting water tab(27.6%) and bucket. 3. Cattle manure was transported by manpower (46%) by loader (34%) and by gravitational flow (14%). Most of manure(97%) was composted after treatment of drying or piling up outside. 4. More instruction and education were required because of the insufficient routine checking and fixing for farming machines, and unsystematic education for learning skills. 5. 65% of farms felt unsatisfied about after service(A/S) for their machinery. The main reason why the farmers were not satisfied was that it took too much time to be repaired. 6. When the farms purchased facilities, equipment and machinery, they did not analyze economic value of them and keep a diary. To make effective use of machines, the most available model for purchasing and managing of machines must be developed and applied to various scales of management.

• Journal of IKEEE
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• v.19 no.1
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• pp.64-72
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• 2015

In this paper, we have developed the gantry automation system via information technology (IT) to improve the productivity of fuel filter manufacturing process. The monitoring system of manufacturing process plays an important role in analyzing the defective products as well as improving the production yield rate. The experimental results of 3 months with 10000 samples validate that the error rate is decreased from 0.65 % to 0.45 %. Also, the defect of raw material is decreased via monitoring of material tools which can notify the time for replacement and accurate insertion of raw materials to the loader. The productivity is increased by reducing the process time from 94.7 sec to 78.8 sec per raw material through comparing the whole manufacturing courses : from inserting of raw material to outcome of product. The process time is decreased by 20.2 % by automation of inserting and outcome course. Moreover, safety of worker as well as reduction of transfer time are highly related with increase of productivity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5357-5365
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• 2013

In this paper, we propose that a model based design for a electric tractor system by using ASM(Automotive Simulation Models). Before developing a realistic electric tractor, it is essential that defining the capacities of power sources and optimizing the parameters of electric tractor. In additionally, because the electric tractor must have not only driving function but also working function, two PMSM are used at electric tractor. ASM which is based on simulink and Carsim were used to design a electric system and powertrain of electric tractor. For verifying the electric tractor system, we compared the design parameters such as max power, state of charge, drive distance, velocity which were carried out by the simulation and experimental method. The predicted results by the development model were in good agreement with the simulation results. According to simulation of tractor, it is possible to arrange the advanced research of dynamical characteristic of tractor and present the guidelines for the electrical driving system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.301-304
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• 2008

The purpose of this study is to embody the integrated working management system for public works, focused on the management of surplus soil at a field of public works. The contents and results of this study can be classified into the design of working management DB for public works and the embodiment of working management DB. First, the design of working management DB for public works consists of three DBs - process management to analyze work plan and performance. for backhoe loader, working management and resources management for equipment and labor management - in connection with work and resources classification system. Secondly, the working management system for public works can describe work plan and performance on a floor plan using graphic. Based on this, the status of process and progress report with visual expression had been developed to facilitate the communications and performance of duties among staff in charge at the field of public works. This study is a specialized system for a company specializing in public works and a system that can be put into practical use if practicality is proved through test-bed with regard to business.