• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.395-399
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• 2017

The LPI fuel filter housings used in automobiles were made from conventional die castings but have recently been developed by cold forging to improve the weight and durability. On the other hand, a sink may develop at the core of the forged product due to the resulting T-shape, which not only reduces the aesthetics, but also increases the post-processing cost of the product. Therefore, this research focused on methods to predict and mitigate sink development and progression during the T-shape forging process. Finite element analysis of the forging process was first performed to determine the optimal initial workpiece devoid of burrs and underfills. An accurate sink prediction was then obtained via metal flow analysis, which was a result of the finite element simulation. Through finite element analysis, it was confirmed that sink development is a product of the differences in nodal velocities arising from the T-shaped forging process. Consequently, a pad was inserted beneath the sink to minimize these velocity differences. The results yielded significant improvement with regard to the sink defect. This method was practically applied to an industrial site to validate the sink improvement.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.271-287
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• 2013

In this study, more convenient model(S-model) for predicting ground surface settlement is developed through comparing field monitoring data of the domestic subway applied shield TBM method with conventional equation & numerical analysis. Sample stations are chosen from whole of excavation section and lateral & vertical ground surface settlement characteristic with excavation are analysed. Based on analysis result, through the comparison with actual monitoring data, the model that is possible to compute maximum surface settlement and settlement influence area is suggested with assumption that lateral surface settlement forms are composed relaxed zone and elastic zone. In addition, vertical ground surface settlement patterns with excavation are similar to cubic-function and S-model with assumption that coefficients are function of tunnel diameter and depth is suggested. Consequently, the ground surface settlement patterns are significantly similar to actual monitoring data and numerical method result. Thus, as a result, when tunnels are excavated using sheild TBM through rather soft weathered soil & rock layer, prediction of ground surface settlement with excavation using convenient S-model is practicable.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.303-310
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• 2013

Thyroid nodular disease is the most frequently appeared in thyroid disease. Thyroid ultrasonography offers location of nodules, size, the number, information of internal echo characteristic. Thus, it makes possible to sort high-risk nodule containing high possibility about thyroid cancer and to induct precisely when take a Fine Needle Biopsy Aspiration. On thyroid nodule, the case which is diagnosed as malignant is less than 5% but screening test is very important on ultrasound and also must be reduced unnecessary procedure. Therefore, in this study an approach for describing a region is to quantity its texture content. We applied TFA algorithm on case which has been pathologically diagnosed as papillary thyroid cancer. we obtained experiment image which set the ROI on ultrasound and cut the $50{\times}50$ pixel size, histogram equalization. Consequently, Disease recognition detection efficiency of GLavg, SKEW, UN, ENT parameter were high as 91~100%. It is suggestion about possibility on CAD which distinguishes thyroid nodule. In addition, it will be helpful to differential diagnosis of thyroid nodule. If the study on additional parameter algorithm is continuously progressed from now on, it is able to arrange practical base on CAD and it is possible to apply various disease in the thyroid US.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.854-862
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• 2014

Attention deficit hyperactivity disorder (ADHD) students' intellctual defects, learning problems, and poor academic achievements seem to be due to significantly lower intelligence compared to the normal students, but rather the characteristic of inability to pay attention at a given time can be seen as the more attributing reason. In this study, a comparison between the ADHD students and the normal students will be performed using a fMRI analysis in order to differentiate the brain function between the two groups during a working memory task performance and to assess the difference in the activated regions of the brain. Clinical survey examinations and fMRI measurements were performed for a group of 26 elementary students from the Incheon area. The stimulus of fMRI was a working memory. Cartography statistically analyzed parameters and the Statistical Package of Social Sciences using single-sample t-test, two-sample t-test, were analyzed by multiple regression analysis, the statistical significance level was p<0.05 in, respectively. The disproportionate developments could be seen in the ADHD students group such as the frontal cortex, parietal cortex, thalamus, and caudate nucleus, among others. In addition, as some students felt the increase in the difficulty of working memory task performance, the orbitofrontal cortex and the hippocampus were activated, which seems to be the result of an effort for looking for an answer. More types of ADHD students needs to be secured as research subjects, and more stimulations for fMRI experiments should be considered as it would be useful in the overall evaluation of brain function.

• The KIPS Transactions:PartB
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• v.11B no.7 s.96
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• pp.759-768
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• 2004

Recently the biometric recognition technology is intensively studied and the standardization of the technology has been highly demanded for its commercialization. Currently many blometric recognition products are being developed based on the BioAPl(Biometric Application Program-ming Interface) specification. However, the reliable testing tools (or scenarios) to evaluate performance and conformance of the products are not shown yet. In this paper, a conformance testing method is presented, which verifies a biometric recognition system to meet the requirements of the BioAPl standard. Two different testing procedures are used in the proposed method. The first procedure evaluates that each functions offered in the BioAPl specification are correctly implemented and that the functions are actually used in the system. Through the Procedure, a BSP(Biometric Service Provider) system is executed on the framework of the BioAPl functions. It requires selection of parameters and prece-dent functions that should be executed first. The second procedure evaluates the abilities of module management, handling operations and ver-ification process by the analysis of the test cases. It tests the correctness of the system operation when a testing scenario is given. The proposed testing method is applied on a fingerprint verification BSP using the sample BSP provided by the BioAPl consortium. The experimental results shows the benefits of the proposed testing method.

• The Transactions of the Korea Information Processing Society
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• v.3 no.2
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• pp.283-294
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• 1996

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the unit control devices located in common manufacturing zone and operated by connecting them. This paper introduces deign and test operation of cell system for the management of multivendor PLC by applying to wall paper process based on the manufacturing standardization of CIM. The analysis of designed multivendor PLC group is performed by selecting the parameters such as variation of data packet size and node number of PLC ladder logic program and variation by analyzing the corresponding variation values of token rotation time and waiting time for the system operation. For the method of the analysis,the equation is considering the overhead such as indicated packet service time and transmission safety margin for PLC network connection in M/G/1 queue model,and it is applied to the cell system and PLC group manage-ment for operation .Through the experiment,it is found that the realtime processing is possible with expanded and better result than the resuit obtained by Jayasumana.Browaka with PLC scan time considered,response lower limit of 10-20 msec. data packet size not more than 50 bytes.and the number of nodes less than 40.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.10
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• pp.387-396
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• 2018

Stock price prediction has been a difficult problem to solve. There have been many studies to predict stock price scientifically, but it is still impossible to predict the exact price. Recently, a variety of types of cryptocurrency has been developed, beginning with Bitcoin, which is technically implemented as the concept of distributed ledger. Various approaches have been attempted to predict the price of cryptocurrency. Especially, it is various from attempts to stock prediction techniques in traditional stock market, to attempts to apply deep learning and reinforcement learning. Since the market for cryptocurrency has many new features that are not present in the existing traditional stock market, there is a growing demand for new analytical techniques suitable for the cryptocurrency market. In this study, we first collect and process seven cryptocurrency price data through Bithumb's API. Then, we use the gradient boosting model, which is a data-driven learning based machine learning model, and let the model learn the price data change of cryptocurrency. We also find the most optimal model parameters in the verification step, and finally evaluate the prediction performance of the cryptocurrency price trends.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.12
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• pp.491-498
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• 2019

Digital twin is a technology that virtualizes physical objects of the real world on a computer. It is used by collecting sensor data through IoT, and using the collected data to connect physical objects and virtual objects in both directions. It has an advantage of minimizing risk by tuning an operation of virtual model through simulation and responding to varying environment by exploiting experiments in advance. Recently, artificial intelligence and machine learning technologies have been attracting attention, so that tendency to virtualize a behavior of physical objects, observe virtual models, and apply various scenarios is increasing. In particular, recognition of each robot's motion is needed to build digital twin for co-robot which is a heart of industry 4.0 factory automation. Compared with modeling based research for recognizing motion of co-robot, there are few attempts to predict motion based on sensor data. Therefore, in this paper, an experimental environment for collecting current and inertia data in co-robot to detect the motion of the robot is built, and a motion prediction model based on the collected sensor data is proposed. The proposed method classifies the co-robot's motion commands into 9 types based on joint position and uses current and inertial sensor values to predict them by accumulated learning. The data used for accumulating learning is the sensor values that are collected when the co-robot operates with margin in input parameters of the motion commands. Through this, the model is constructed to predict not only the nine movements along the same path but also the movements along the similar path. As a result of learning using SVM, the accuracy, precision, and recall factors of the model were evaluated as 97% on average.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.649-657
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• 2019

An essential part of the development of an autonomous ship is supporting technology that can effectively check and diagnose the operational status of the ship form the shore control center on land. This development has recently occurred in the shipbuilding and shipping industries. In this paper, we present a smart ship solution that operates, as a single system, a data collection platform that gathers ship operation data and a service platform that provides various services. When this smart ship solution was applied to an operating ship, it was determined that a variety of high-quality data could be collected compared to existing ship data collection systems. In addition, it was shown that of the operation data collected, analysis of parameters related to the main engine can be used to determine the overall state by deriving valid results and visualizing patterns. In conclusion, it was suggested that a ship's operation status could be checked more effectively and a comprehensive evaluation could be possible at the shore control center if the results of this study were extended to various ship equipment and analyzed together with the operational environment data.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.228-235
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• 1981

Ultraviolet spectrophotometric investigation were carried out on the systems of pyridine, ${\beta}$-picoline and 3,5-lutidine with iodine in carbon tetrachloride. The results reveal the formation of one to one molecular complexes of the type, $C_5H_5N{\cdot}I_2$, ${\beta}-C_5H_4(CH_3)N{\cdot}I_2$ and 3,5-$C_5H_3(CH_3)_2N{\cdot}I_2$. The equrilibrium constants of complexes were obtained in consideration of that absorption maxima have the blue shift with the increasing temperatures according to the formation of the charge transfer complexes. The thermodynamic parameters, ${\Delta}H$, ${\Delta}G$ and ${\Delta}S$ for the formation of the charge transfer complexes were calculated from these values. These results indicated that the relative stabilities of the pyridine, ${\beta}$-picoline and 3,5-lutidine complexes with iodine increase in the order, pyridine < ${\beta}$-picoline < 3,5-lutidine. These results were supposed to be the influence resulted from increase of electron density by the positive inductive effect and the dipole moment of the steric hindrance effect. And this results were compared and discussed with polymethylbenzene-iodine CT-complexes.