• Journal of Biosystems Engineering
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• v.5 no.1
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• pp.1-14
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• 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 Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.226.2-227
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• 2003

The degree of milling is an important factor in terms of the nutritional value and the economic return of the milled rice. This study was to investigate the changes in compositions of the oils obtained from rice with different degree of milling. The content of total tocols in rice significantly (p＜0.05) decreased, as degree of milling increased. The relative ％ of -tocopherol in brown rice had lower than those in milled rices whereas the relative ％ of -tocotrienol, and -tocotrienol in brown rice higher than those in milled rices. -Oryzanol content significantly (P<0.05) decreased from 198.5 mg/kg rice for brown rice (0% milling) to 65.5 125.0 mg/kg rice for rice samples with 5.6, 8.0, and 9.6 ％ milling. -Sitosterol was most abundant sterol representing 50 ％ - 56% of the total sterol content in all analyzed samples. The content of total sterol as well as each sterol isomers in rice significantly (P<0.05) decreased, as degree of milling increased. A similar trend was observed in changes of octacosanol and squalene.

• Environmental and Resource Economics Review
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• v.28 no.3
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• pp.415-435
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• 2019

The purpose of this study is to analyze the returns to scale by estimating the bigeye tuna production function of Korean distant longline fisheries in WCFPC waters. In the analysis, number of crews, vessel tonnage, number of hooks, and bigeye tuna biomass are used as input variables and the catch amount of bigeye tuna is used as an output variable in the Cobb-Douglas production function. Prior to the function estimation, the biomass of bigeye tuna was estimated by the Bayesian state-space model. Results showed that the fixed effect model was selected based on the hausman test, and vessel tonnage, hooks, and biomass would have direct effects on the catch amount. In addition, it was shown that the bigeye tuna distant longline fisheries in WCFPC water would have increasing returns to scale.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.129-134
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• 1997

The purpose of this study is to estimate the distribution rate of R&D input on R&D output in major manufacturing industrial sector. The distribution rate is estimated on time-series data for the period 1980 to 1996. The data used in this study can be divided into the two categories. 1) R&D output data (Patent, Utility) 2) R&D input data (R&D expenditure, R&D workers) The raw data of R&D expenditure is transformed into R&D stock. And the specific production function is used to represent the interaction between R&D input and output. The production function shows the maximum rate of R&D output that can be achieved by certain given, technologically possible, R&D input combinations. The main findings can be summarized as follows. 1) There was a diminishing return between R&D input and output$(\alpha+\beta<1). 2) R&D output growth was more affected by R&D expenditures than R&D workers. 3) R&D workers were more contributed highly to Patent granted than Utility model.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.61-70
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• 2020

As mobile device usage time increases thanks to the development of information and communication alongside the increase in the spread of smartphones, mobile shopping has become a common trend. While mobile shopping has the advantage of saving both time and money, it may also result in dissatisfaction with product differences after purchase. For online clothing shopping malls, in particular, if the size does not match after purchase, it is difficult for customers to return or exchange the goods. To address this problem, some mobile apparel shipping malls offer a virtual fitting service and a size comparison function; however, the number of such malls remains low. In this paper, a usability evaluation was performed on a mobile apparel shopping mall that provides a size comparison function. The three apps selected for evaluation have different size input methods, and a slightly different method of providing results after comparing the user's dimensions with the dimensions of the clothes to be purchased. In this paper, the evaluators were asked to select clothes at the shopping mall and perform the task of deciding the size of the clothes to be purchased through their own measurements and comparison while also evaluating the effectiveness, meaning, and satisfaction of the apps. Based on the analysis of the results, this paper aims to produce an improvement plan and help design the size comparison UI (User Interface) in the future.

• Journal of Korean Physical Therapy Science
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• v.6 no.4
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• pp.187-199
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• 1999

Functional Electrical Stimulation (FES) is used for muscle reeducation, reduction of spasticity, delay of atrophy, and muscle strengthening. FES stronger stimulation than other forms of electrical stimulation. The efficacy of FES in improving function has been substantiated in the literature. Treatment programs employing FES - activation of muscular tissue through the intact peripheral nervous system - can be broken into five major categories, according to the goal of treatment. These broad areas would include the use of FES to: (1) a direct excitation onto the alpha motoneuron, through peripheral stimulation of the Ia myotatic sensory system and ascending afferent information, which will be integrated at conscious and subconscious level of the CNS. (2) The quality of a stimulated muscle contraction is determined by combination of many parameters, including stimulus amplitude, pulse duration, stimulus frequency, and duty cycle. (3) A unit that has a pulse duration between 200 and $400{\mu}sec$ will be more than adequate for FES applications. (4) The neuromuscular plasticity is critically important to return of function using muscle re-education and facilitation applications. (5) Prior to using FES as an electrical orthosis, the patient should build up endurance in the muscles to be stimu1ated during the gait cycle.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.6
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• pp.703-714
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• 2001

In C language, a local buffer overflow in stack can destroy control information stored near the buffer. In case the buffer overflow is used maliciously to overwrite the stored return address, the system is exposed to serious security vulnerabilities. This paper analyzes the process of buffer overflow hacking and methodologies to avoid the attacks in details. And it proposes a device of static buffer overflow detection by using function summary and tracking information flow of buffer domain at assembly source code level(SASS, Static Assembly Source code Scanner) and then show the feasibility and validity of it by implementing a prototype in Pentium based Linux environment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.2
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• pp.152-155
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• 2007

In this study, we fabricated FBAR(film bulk acoustic resonator) by using $Li_{2}CO_{3}:ZnO$ as a function of annealing temperature and concentrated on effect of frequency characteristic of FBAR. The results show that the annealing affects resistivity and crystallity. The optimum properties were observed for film annealed at $500^{\circ}C$. The resistivity was $1.5{\times}10^{11}\;{\Omega}{\cdot}cm$ and the roughness was 21.10 nm. And the return loss is improved from -24.9 at $300^{\circ}C$ to -29.8 at $500^{\circ}C$ without the resonant frequency change. We finally confirmed the improvement on the frequency characteristics of FBAR device by annealing process at the optimized condition.

• Wind and Structures
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• v.25 no.3
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• pp.261-282
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• 2017

The probabilistic information of directional extreme wind speeds is important for precisely estimating the design wind loads on structures. A new joint probability distribution model of directional extreme wind speeds is established based on observed wind-speed data using multivariate extreme value theory with the t-Copula function in the present study. At first, the theoretical deficiencies of the Gaussian-Copula and Gumbel-Copula models proposed by previous researchers for the joint probability distribution of directional extreme wind speeds are analysed. Then, the t-Copula model is adopted to solve this deficiency. Next, these three types of Copula models are discussed and evaluated with Spearman's rho, the parametric bootstrap test and the selection criteria based on the empirical Copula. Finally, the extreme wind speeds for a given return period are predicted by the t-Copula model with observed wind-speed records from several areas and the influence of dependence among directional extreme wind speeds on the predicted results is discussed.

• KDI Journal of Economic Policy
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• v.40 no.4
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• pp.1-22
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• 2018

We estimate three continuous-time stochastic volatility models following the approach by Aït-Sahalia and Kimmel (2007) to compare the Korean and US stock markets. To do this, the Heston, GARCH, and CEV models are applied to the KOSPI 200 and S&P 500 Index. For the latent volatility variable, we generate and use the integrated volatility proxy using the implied volatility of short-dated at-the-money option prices. We conduct MLE in order to estimate the parameters of the stochastic volatility models. To do this we need the transition probability density function (TPDF), but the true TPDF is not available for any of the models in this paper. Therefore, the TPDFs are approximated using the irreducible method introduced in Aït-Sahalia (2008). Among three stochastic volatility models, the Heston model and the CEV model are found to be best for the Korean and US stock markets, respectively. There exist relatively strong leverage effects in both countries. Despite the fact that the long-run mean level of the integrated volatility proxy (IV) was not statistically significant in either market, the speeds of the mean reversion parameters are statistically significant and meaningful in both markets. The IV is found to return to its long-run mean value more rapidly in Korea than in the US. All parameters related to the volatility function of the IV are statistically significant. Although the volatility of the IV is more elastic in the US stock market, the volatility itself is greater in Korea than in the US over the range of the observed IV.