• Journal of Biosystems Engineering
• /
• v.5 no.1
• /
• pp.1-14
• /
• 1980

Threshing operation may be one of the most important processes in the paddy post-production system as far as the grain loss and labor requirement are concerned . head-feeding type threshers commercially available now in Korea originally were developed for threshing dry paddy in the range of 15 to 17 % in wet basis. However, threshing wet-paddy with the grain moisture content above 20 % has been strongly recommended, especially for new high-yielding Indica -type varieties ; (1) to reduce high grain loss incurred due to the handling operations, and (2) to prevent the quantitative and qualitative loss of milled -rice when unthreshed grains are rewetted due to the rainfall. The objective of this study were to investigate the adaptability of both a head-feeding type thresher and a throw-in type thresher to wet-paddy , and to find out the possiblilities of improving the components of these threshers threshing. Four varieties, Suweon 264 and Milyang 24 as Tongil sister line varieties, minehikari and Jinhueng as Japonica-type varieties, were used at the different levels of the moisture content of grains. Both the feed rate and the cylinder speed were varied for each material and each machine. The thresher output quality , composition of tailing return, and separating loss were analyzed from the sampels taken at each treatment. A separate experiment for measurement opf the power requirement of the head-feeding type thresher was also performed. The results are summarized as follows : 1. There was a difference in the thresher output quality between rice varieties. In case of wet-paddy threshing at 550 rpm , grains with branchlet and torn heads for the Suweon 264 were 12 % and 7 % of the total output in weight, respectively, and for the Minehikari 4.5 % and 2 % respectively. In case of dry paddy threshing , those for the Suweon 264 were 8 % and 5% , and for the Minehikari 4% and 1% respectively. However, those for the Milyang 23 , which is highly susceptable to shattering, were much lower with 1 % and 0.5% respectively, regardless of the moisture content of the paddy. Therefore, it is desirable to breed rice varieties of the same physical properties as well as to improve a thresher adaptable to all the varieties. Torn heads, which increased with the moisture content of rall the varieties except the Milyang 23 , decreased as the cylinder speed increased, but grains with branchlet didnt decrease. The damaged kernels increased with the cylinder speed. 3. The thresher output quality was not affected much by the feed rate. But grains with branchlet and torn heads increased slightly with the feed rate for the head-feeding type thresher since higher resistance lowered at the cylinder speed. 4. In order to reduce grains with branchlet and torn heads in wet-paddy threshing , it is desirable to improve the head-feeding type thresher by developing a new type of cylinder which to not give excess impact on kernels or a concave which has differenct sizes of holes at different locations along the cylinder. 5. For the head-feeding type thresher, there was a difference in separating loss between the varieties. At the cylinder speed of 600 rpm the separating losses for the Minehikari and the Suweon 264 were 1.2% and 0.6% respectively. The separating loss of the head-feeding type thresher was not affected by the moisture content of paddy while that of the Mini-aged thresher increased with the moisture content. 6. From the analysis of the tailings return , to appeared that the tailings return mechanism didn't function properly because lots of single grains and rubbishes were unnecessarily returned. 7. Adding a vibrating sieve to the head-feeding type thresher could increase the efficiency of separation. Consequently , the tailing return mechanism would function properly since unnecessary return could be educed greatly. 8. The power required for the head-feeding type thresher was not affected by the moisture content of paddy, but the average power increased linearly with the feed rate. The power also increased with the cylinder speed.

• Proceedings of the Korean Printing Society Conference
• /
• 2007.11a
• /
• pp.13-28
• /
• 2007

Producing printing plate is essential progress to do offset printing. In this Film-less period, the more PS plate becomes extinct, the more the age of the Plate-Making of Exposure declines the place to stand. To do offset printing, the CTP (Computer to Plate) is taking a place of PS plate that covers speed, quality and economical problems. The biggest advantage of using CTP is that laser directly goes to the plate, thus there are no dust from the Plate-Making of Exposure. It is also theoretically able to print 200lpi${\sim}$300lpi as well as print 1751pi, because it has over 2400dpi resolution. The high quality printing could be available inside of the country, if printing machine keeps the optimum condition in offset printing. The CTP has many advantages, however there is a difficulty for the operators to preserve the equipment. The actual circumstance is that they cannot make a decision about how many dots need to be generated, and also it is necessary to know how to establish the setup at RIP on CTP to make the optimum condition output. If offset printing machine keeps the optimum condition, it would be able to print up to high quality printing however it is hard to comment what is the optimum condition for the printing machine. Anyone could say easy subjectively that machine is in the optimum condition, however it is objectively hard to estimate by number. In this research GATF / Plate Test target used to analyze the image and to make numerical value of the optimum condition of the CTP. It also used GATF / The sheep fed test printing 5.0 to know the density of the color representation, dot gain and gray balance for the optimum condition of the print machine. The purpose of this research is to represent the ISO 12647-2 which is the international standard with domestic printing equipments.

• Journal of Biosystems Engineering
• /
• v.28 no.3
• /
• pp.187-198
• /
• 2003

This study was conducted to investigate the effect of design parameters of modulating valve and hydraulic clutch on the shift quality of a power shuttle transmission using a computer simulation. Computer simulation models of a hydraulic control system and a power shuttle drive train were developed and verified by an experimental power train in a laboratory. The software EASY5 was used for the modeling and simulation of the power shuttle transmission. Results of the study were summarized as follows: For a good shift quality. it is required to reduce the transient torque transmitted to the output shaft of the transmission as much as possible. This may be achieved by reducing the modulating time and clutch pressure. It was found that the design parameters most significantly affecting the modulating time and clutch pressure were the spring constant and displacement of a load piston of the modulating valve, and the spring constant and damping of the clutch piston. The modulating time decreased as the spring constant increased and increased as the displacement of the load piston decreased. The transient torque decreased as the modulating time increased. However their relationships were not always linear. As the damping decreased, both the modulating pressure and time decreased, which also resulted in a decrease in the transient torque. The spring constant of the clutch piston affected the modulating time and the peak transient torque. As the spring constant of the clutch increased, the peak transient torque decreased.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.73-78
• /
• 2003

In this research, we implement Realtime Air Diffusion Prediction System which is a parallel Fortran model running on distributed-memory parallel computers. The system is designed for air diffusion simulations with four-dimensional data assimilation. For regional air quality forecasting a series of dynamic downscaling technique is adopted using the NCAR/Penn. State MM5 model which is an atmospheric model. The realtime initial data have been provided daily from the KMA (Korean Meteorological Administration) global spectral model output. It takes huge resources of computation to get 24 hour air quality forecast with this four step dynamic downscaling (27km, 9km, 3km, and lkm). Parallel implementation of the realtime system is imperative to achieve increased throughput since the realtime system have to be performed which correct timing behavior and the sequential code requires a large amount of CPU time for typical simulations. The parallel system uses MPI (Message Passing Interface), a standard library to support high-level routines for message passing. We validate the parallel model by comparing it with the sequential model. For realtime running, we implement a cluster computer which is a distributed-memory parallel computer that links high-performance PCs with high-speed interconnection networks. We use 32 2-CPU nodes and a Myrinet network for the cluster. Since cluster computers more cost effective than conventional distributed parallel computers, we can build a dedicated realtime computer. The system also includes web based Gill (Graphic User Interface) for convenient system management and performance monitoring so that end-users can restart the system easily when the system faults. Performance of the parallel model is analyzed by comparing its execution time with the sequential model, and by calculating communication overhead and load imbalance, which are common problems in parallel processing. Performance analysis is carried out on our cluster which has 32 2-CPU nodes.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.25 no.2
• /
• pp.69-84
• /
• 2007

Producing printing plate is essential progress to do offset printing. In this Film-less period, the more PS plate becomes extinct, the more the age of the Plate-Making of Exposure declines the place to stand. To do offset printing, the CTP (Computer to Plate) is taking a place of PS plate that covers speed, quality and economical problems. The biggest advantage of using CTP is that laser directly goes to the plate, thus there are no dust from the Plate-Making of Exposure. It is also theoretically able to print $200lpi{\sim}300lpi$ as well as print 1751pi, because it has over 2400dpi resolution. The high quality printing could be available inside of the country, if printing machine keeps the optimum condition in offset printing. The CTP has many advantages, however there is a difficulty for the operators to preserve the equipment. The actual circumstance is that they cannot make a decision about how many dots need to be generated, and also it is necessary to know how to establish the setup at RIP on CTP to make the optimum condition output. If offset printing machine keeps the optimum condition, it would be able to print up to high quality printing however it is hard to comment what is the optimum condition for the printing machine. Anyone could say easy subjectively that machine is in the optimum condition, however it is objectively hard to estimate by number. In this research GATF / Plate Test target used to analyze the image and to make numerical value of the optimum condition of the CTP. It also used GATF / The sheep fed test printing 5.0 to know the density of the color representation, dot gain and gray balance for the optimum condition of the print machine. The purpose of this research is to represent the ISO 12647-2 which is the international standard with domestic printing equipments.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.43 no.5 s.311
• /
• pp.48-56
• /
• 2006

In this paper, we proposed the high quality audio watermarking algorithm using MDCT/IMDCT (Modified DCT/Inverse Modified DCT) with psychoacoustic model. Generally, a digital audio watermark is embedding the frequency domain after frequency transform of the digital audio data but the digital audio quality is affected by watermarking. In our scheme, the digital audio data is spread with PN((Pseudo Noise) code and then audio watermark is embedded in MDCT processing that refers psychoacoustic model. In MDCT processing, according to the shape of filter bank output, the block switching selects a window sequence that has 256, 1,024 or 2,048 points interval for high quality audio. The author confirm that when watermark weight ${\alpha}$ is 2.5 below, the detection ratio of watermark is a satisfied to SDMI's(Secure Digital Music Initiative) recommendation 50% above and SM is $50{\sim}68dB$ range with mainly 4 kind of attacks(Compression, Cropping, FFT and Echo).

• Journal of Agricultural Extension & Community Development
• /
• v.16 no.2
• /
• pp.285-304
• /
• 2009

The objectives of this study were finding out some methods about development of oversea agriculture in Korea. It is a tough task that faces us now. China is a big agricultural country, most agricultural investment country and the nearest located in Korea. So this study researches on the quality of farmers and characters of rural human resources in China. In China, agriculture industry is the basic industry among national economy developments. The majority of populations in China are living in rural region. Agriculture, villages and farmers are main issues in China. From this point, An analysis of Chinese farmers' characters and qualities; general conditions of farmers' knowledge of science and technology, their education level, quality of minds and sprit, and rural public health service situation in China. The result of this study is following; First, Chinese farmers' factors that low education level, big cultural differences between cities and country sides affect the development of China's agriculture as obstruction factors. Second, Practice conditions of farmers' science knowledge and technology are low level, output of higher rural human resources, low quality of minds and sprit and problems of agricultural extension service. It is negative influenced of agriculture and farmers economic development in China. Third, unsociable culture of the peasantry influences Chinese farming in the negative ways. Also, conventional notions of family are getting weaker, it makes connection of the kinship weaken. But, Chinese think that this kind of kinship is the most important thing in their life. Fourth, in the case of situations that the farmer's sanitation and health, low level of the medical service is getting worse than before relatively. And there are a lot of discordances between a planned childbirth policy and personal recognitions. Also, lacking of nourishment makes labor productivity falling tendencies. The medical industry falls short of the standard as compared to the number of farming people. Fifth, in the peasantry's consciousness of the legal system, this causes difficulties to farmers in the market. Shortage of the legal knowledge exerts a bad influence upon rural economy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2015.10a
• /
• pp.51-52
• /
• 2015

IMO has been proceeding in the maritime SQA for software quality is considered to be essential for the development of the introduction of the e-Navigation. In order to ensure software quality, follow the prescribed procedures throughout the software development project and create the output as a result of executing the respective steps. This paper is introduced a case for applying to maritime software development using the tool that is capable of real-time monitoring and automated documentation. Also, it is discussed the improvement of procedures for applying the expected effects and maritime SQA for thr tool utilization. The Development of customized tools for maritime SQA that is reflected an improved procedure for tool is the future goals.

• Plant Journal
• /
• v.8 no.4
• /
• pp.34-39
• /
• 2012

This study presents how low quality coal combustion affects the desulfurizer draft system by correlating of draft loss in a coal-fired thermal power plant and predicts the stall occurrence time of a booster fan. In case of low quality coal, a lot of coal is needed to generate equivalent output power, thereby the rating of increasing draft loss was faster than designed amount of coal. We surely confirmed that draft loss affects the specific energy of a booster fan strongly. On this basis, it is possible to predict the occurring time of stall for a booster fan from current operation specific energy to stall limit specific energy. This study suggests increasing speed of draft loss in each caloric value and the impact of specific energy at a booster fan, it expects to help safe operating in a thermal power plant.

• Journal of KIISE:Information Networking
• /
• v.37 no.5
• /
• pp.403-408
• /
• 2010

The sensor nodes can be installed in the environment in which the temperature change is considerable, such as desert, urban, and data center. Particularly, because the output power becomes less than the targeted power if a temperature is increasing, link quality is degraded and packet losses are occurred. In order to compensate the temperature changes, existing schemes detect the change of the link quality between nodes and control transmission power through a series of feedback process. However, these approaches can cause heavy overhead by additional control packets. In this paper, we propose the T2PC(Temperature-aware Transmission Power Control) to keep up the link quality despite temperature variation. At each node, T2PC compensates the attenuated link quality by controlling the transmission power based on the local temperature measurement. In addition, the packet reception ratio can be improved with less control packets than ones required in existing transmission power control methods based on the feedback control.