• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.107.1-107.1
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• 2012

Because of beautiful glossy and color, the value of gold leverage is very high in Europe. For improve the quality of white gold, we performed heat treatment on 14K white gold alloys at various age-hardening conditions. Age-hardening behavior and the related phase transformation changes were studied to elucidate the hardening mechanism of 14K white gold alloys. For solid solution treatment [ST], casted 14K white gold alloy specimens were treated at high temperature ($750^{\circ}C$) during 30 minute, and the specimens dropped to water for quenching immediately. For Age-hardening treatment [AT], the specimens were treated at various temperatures ($250^{\circ}C{\sim}300^{\circ}C$). After the heat treatment, we observed increased hardness from 144 Hv to 214 Hv by Vicker's hardness tester. Variation of the grain size measured by optical microscopy (OM) and scanning electron microscopy (SEM) images. By electron probe micro-analysis (EPMA) mapping analysis, we investigated that irregular particles were changed uniformly. After heat treatment, 14K white gold alloys showed improved hardness and became uniformity of grain size by age-hardening treatment.

• Korean System Dynamics Review
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• v.1 no.2
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• pp.149-174
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• 2000

In recent years, how to promore the Utilization of Internet is a main issue of national information policy. In this study, we focused our approach to find promoting sttategies for Internet utilization on three sector's users, governments, enterprises, and households. Promoting the Internet utilization of these three sector's users is a very difficult problem, because their information levels are different and information gap among them can be regarded as bottleneck. And since the interactions between user's demands and diverse information seccor's factors are very complex, policy leverages can not find easily. By the system dynamics methodology, this paper examines the interrelationships between three user's demand mechanism and information policy sector. Information policy sector consist of four sectors, infrastruccure policy seccor, application-contents sector, governance sector, and access and price policy sector (free access policy, literacy policy, telecommunication price policy, etc.). To find and investigate policy leverage that will help understanding dynamic behavior of users in using Internet we build a causal loop diagrams and SD models by using survey data obtained from three sectors'specialized users, 488 persons.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1010-1012
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• 2015

Interest in fossil fuels, alternative energy development in the world has increased significantly. That interest in solar systems increase significant and technology for efficiency and effective operation of PV technology, we expect to continue. This section provides the necessary information to users, and introduce the client system for mobile monitoring real-time solar system information, without the constraints of location or time, and leverage real-time information transmitted tell me about the expected effects that you can get to evaluate.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.189-198
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• 2021

In this paper, we introduce the software/hardware system that can reliably calculate the distance from sensor to the model regardless of point cloud density. As the 3d point cloud map is widely adopted for SLAM and computer vision, the accuracy of point cloud map is of great importance. However, the 3D point cloud map obtained from Lidar may reveal different point cloud density depending on the choice of sensor, measurement distance and the object shape. Currently, when measuring map accuracy, high reflective bands are used to generate specific points in point cloud map where distances are measured manually. This manual process is time and labor consuming being highly affected by Lidar sparsity level. To overcome these problems, this paper presents a hardware design that leverage high intensity point from three planar surface. Furthermore, by calculating distance from sensor to the device, we verified that the automated method is much faster than the manual procedure and robust to sparsity by testing with RGB-D camera and Lidar. As will be shown, the system performance is not limited to indoor environment by progressing the experiment using Lidar sensor at outdoor environment.

• International journal of advanced smart convergence
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• v.13 no.2
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• pp.61-68
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• 2024

In the quest for advancing diabetes diagnosis, this study introduces a novel two-step machine learning approach that synergizes the probabilistic predictions of Logistic Regression with the classification prowess of Random Forest. Diabetes, a pervasive chronic disease impacting millions globally, necessitates precise and early detection to mitigate long-term complications. Traditional diagnostic methods, while effective, often entail invasive testing and may not fully leverage the patterns hidden in patient data. Addressing this gap, our research harnesses the predictive capability of Logistic Regression to estimate the likelihood of diabetes presence, followed by employing Random Forest to classify individuals into diabetic, pre-diabetic or nondiabetic categories based on the computed probabilities. This methodology not only capitalizes on the strengths of both algorithms-Logistic Regression's proficiency in estimating nuanced probabilities and Random Forest's robustness in classification-but also introduces a refined mechanism to enhance diagnostic accuracy. Through the application of this model to a comprehensive diabetes dataset, we demonstrate a marked improvement in diagnostic precision, as evidenced by superior performance metrics when compared to other machine learning approaches. Our findings underscore the potential of integrating diverse machine learning models to improve clinical decision-making processes, offering a promising avenue for the early and accurate diagnosis of diabetes and potentially other complex diseases.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.101-111
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• 2012

In this paper, the feedback loop mechanisms among the operational indices and exogenous variables of a sewerage system that are inherent in the operation and maintenance of a sewerage system were identified using the System Dynamics (SD) modeling methodology. The identified feedback loops were used to develop a SD computer simulation model that can be used to predict future operational conditions of a sewerage system and identified the efficient ways of operation. The data of Busan metropolitan city sewerage system was applied to verify the developed SD model and predict future operational conditions of the system. As a result, it was predicted that sewage treatment efficiency, volume of sewage treatment and cost recovery rate will be gradually increased, whereas service rate which was already very close to the target will remain almost the same as the current value. Furthermore, sensitivity analysis concerning some operational indices was performed in order to discover the policy leverage. As a result, it was found that the exogenous variables related to the pipe maintenance had a great effect on facility using rate, volume of sewage treatment as well as sewage treatment efficiency.

• 사회경제평론
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• v.29 no.1
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• pp.119-154
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• 2016

Kalecki thought that monetary and financial factors play very important roles in the processes of investment decision and expenditure. He also acknowledged that interest rate is monetary phenomenon and investment finance is provided by banks prior to savings as Keynes did, and suggested that the more is the debt, the greater is the risk of debtor and lender. However, in developing investment theory he dismissed those monetary and financial factors or substituted into actual profit or savings, because he aimed to construct the investment theory to be able to explain the 'automatic mechanism of the fluctuation of capitalist economy'. Thus it is argued that Kalecki did not consider the monetary and financial factors in his investment theory. This paper aims to modify Kalecki's investment theory so that it incorporates the monetary and financial factors, such as the willingness of banking system to lend, interest rates, the ratio of leverage which had been dismissed by him. The Kaleckian investment theory that incorporates the monetary and financial factors in Kalecki's theory of investment allows us to explain not only an automatic and regular business cycle, but also irregular excessive investment and high leverage, consequent risk increase and financial crisis occurred in the economy with developed financial system.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.22
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• pp.255-285
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• 2004

After more than 15 years of negotiations, China was finally able to achieve the WTO membership, opening up new trade opportunities for China as well as existing WTO members. China accepted a special safeguard mechanism as one of its WTO- plus commitments. And in response, Korea has since introduced China special safeguard rules, which in simple terms, allows an invocation of safeguard measures against Chinese product imports under more lapse conditions than would normally be allowed under the existing general safeguard rules. China also introduced new safeguard rules in November 2001 in an effort to increase transparency in its operation of safeguard measures. However, the current article contends that the new rules pose a serious threat to free trade in the form of the retaliation provision, which enables China to take unilateral retaliatory actions against safeguard measures on Chinese product imports, It indicates that the provision could be operated in an arbitrary manner as the US Super 301, and lead to infringements of WTO disciplines. This paper indicates that the foregoing elements could lead to mort trade disputes between Korea China regarding safeguard measures and subsequent retaliations on the hills of the so called the Garlic War. The current article goes on to offer policy recommendations toward deterring such disputes. First, it recommends a more active invocation of Korea's own retaliatory provision against China's unilateral actions at least to gain negotiating leverage. Second, it sites problems involving China's still conspicuous state-trading practices, and proposes to raise issues again China to induce more faithful implementation of WTO disciplines Final, it stresses the importance of preventing disputes before they arise, and suggests several specific preventive measures.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.283-283
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• 2013

Because of beautiful glossy and color, the value of gold leverage is very high in Europe. To improve the quality of gold alloys, we performed heat treatment on 14 K white gold alloys by variously changing age-hardening conditions. Age-hardening behavior and the related phase transformation changes were studied to elucidate the hardening mechanism of 14 K white gold alloy. For solid solution treatment [ST], casted gold alloy specimens were treated at high temperature ($750^{\circ}C$) for 30 minutes, and the specimens dropped to water to quench them. For Age-hardening treatment [AT], the specimens were treated at various temperatures ($250{\sim}300^{\circ}C$). After the heat treatment, we observed the phenomenon to increase hardness from 126 Hv to 166 Hv by Vicker's hardness tester. Through electron probe micro-analysis (EPMA) mapping analysis, we investigated that irregular particles were changed uniformly. In the SEM and OM images, two phases of matrix and particle-likestructures were observed, and the precipitation of these elements from the matrix progressed during age-hardening. By transmission electron microscope and X-ray diffraction observation, it was revealed that the formation of the Au3Cu superstructure contributed to the age-hardening at $270^{\circ}C$ in the gold alloy. After the heat treatment, this analysis shows that casted gold alloys were to improve hardness and to moderate surface defects at specific temperatures and duration.

• Journal of KIISE
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• v.42 no.1
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• pp.15-22
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• 2015

In this paper, we present a case study for a drug repositioning simulation based on distributed supercomputing technology that requires highly efficient processing of large-scale computations. Drug repositioning is the application of known drugs and compounds to new indications (i.e., new diseases), and this process requires efficient processing of a large number of docking tasks with relatively short per-task execution times. This mechanism shows the main characteristics of a Many-Task Computing (MTC) application, and as a representative case of MTC applications, we have applied a drug repositioning simulation in our HTCaaS system which can leverage distributed supercomputing infrastructure, and show that efficient task dispatching, dynamic resource allocation and load balancing, reliability, and seamless integration of multiple computing resources are crucial to support these challenging scientific applications.