• Journal of KIISE:Computing Practices and Letters
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• v.16 no.5
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• pp.621-625
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• 2010

This paper presents a hand motion tracking method for hand gesture interface using a camera in mobile devices such as a smart phone and PDA. When a camera moves according to the hand gesture of the user, global optical flows are generated. Therefore, robust hand movement estimation is possible by considering dominant optical flow based on histogram analysis of the motion direction. A continuous hand gesture is segmented into unit gestures by motion state estimation using motion phase, which is determined by velocity and acceleration of the estimated hand motion. Feature vectors are extracted during movement states and hand gestures are recognized at the end state of each gesture. Support vector machine (SVM), k-nearest neighborhood classifier, and normal Bayes classifier are used for classification. SVM shows 82% recognition rate for 14 hand gestures.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.41-58
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• 2003

A recent trend of global shipping industry adopting Port State Control (PSC) system is recognized as a proficient mechanism in preventing costal traffic accident and protecting marine environment. Disadvantages of Korean shipping companies in PSC inspection are unavoidable as Tokyo MOU imposed priority listed flag to Korea. Having stated above, appropriate research and prompt preparation in compliance with current PSC requirements for the Korean shipping companies have become an immediate need. The objectives of this study are : First, to review in understanding of PSC in overall and foundation of enforcement. Second. to study interaction of international treaties regarding PSC. Third, to compare practical compliance among the countries and to open up a case study on Korean shipping companies in adopting PSC. Last, to suggest direction to the Korean shipping companies the most proficient way in compliance with the current Tokyo MOU requirement. Korean flagged vessels have become prioritized target in PSC inspection as Tokyo MOU imposed priority listed flag to Korea due to high detention rate of its fleet. Disadvantage of a priority listed flag is a burden in its proficient fleet operation. This study suggests solutions to the disadvantages as below. : 1) Change shore management system, and provide continuous & quality education to crew members 2) Form a network in sharing PSC information among the Korean shipping companies 3) Form a centralized function in which government, Korean Shipping register and shipowners can treat problems in a prompt manner.

• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.851-864
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• 2010

We investigated the sensitivity of Korean streamflows to climate variation. Historical dam inflows and climate data for eight multi-purpose dam sites were collected and examined to determine key factors affecting streamflow change. The results show that annual streamflow primarily responds to change in precipitation rather than temperature. However, the combination of less precipitation and high temperature induces a more serious decrease in streamflow than does similar precipitation and with low temperature. This result indicates that Korean water resources could be more vulnerable to drought due to increasing temperature caused by global warming. To estimate spatial differences in climate sensitivity, we also calculated climate elasticity for 109 mid-size watersheds using streamflow simulated by the Precipitation Runoff Modeling System (PRMS). Climate elasticity ranges over 1.5~1.9, indicating that a +20% increase in annual precipitation leads to a +30~+38% increase in annual streamflow.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.2
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• pp.79-86
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• 2017

Precise Point Positioning-Real Time Kinematic (PPP-RTK) refers to a technology that combines PPP with network-RTK in which a user does not directly receive observed data from a reference station but receives State-Space Representation (SSR) messages corrected for error components from a central processing station through Networked Transport of RTCM via Internet Protocol (NTRIP) or Digital Multimedia Broadcasting (DMB) for purposes of positioning. SSR messages, which refer to corrections used in PPP-RTK, are generated by a central processing station using real-time observed data collected from reference stations and account for corrections needed due to the ionosphere, troposphere, satellite orbital errors, satellite time offsets, and satellite biases. This study used a type of SSR message provided in South Korea, known as Korea-SSR (K-SSR), to implement a PPP-RTK algorithm based on code-pseudorange measurements and validated its accuracy within the reference station network. In order to validate the accuracy of the implemented algorithm outside of the network, the K-SSR was extrapolated and applied to positioning in reference stations in Changchun, China (CHAN) and Japan (AIRA). This also entailed a quantitative evaluation that measured improvements in accuracy in comparison with point positioning. The results of the study showed that positioning applied with extrapolated K-SSR correction data was more accurate in both AIRA and CHAN than point positioning with improvements of approximately 20~50%.

• International Commerce and Information Review
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• v.18 no.2
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• pp.85-103
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• 2016

This study deals with a research on Korean American economy and Korean banks operated in California where a large percentage of Korean residents in the U.S. is concentrated. Using date published by U.S. Census and the Federal Deposit Insurance Corporation (FDIC), quantitative analyses have been performed on the asset, employment, market share and other features of selected Korean American financial institutions. Also, each bank's status of financing and asset management are reviewed through the analysis of its balance sheets. The outcome of analysis on the status of Korean American banks are summarized as follows: First, Korean American banks are shown to be growing to become major banks with equivalent scale as mainstream banks. Second, the recently improved fundamentals of Korean American banks are identified. Third, the operational performances of Korean American banks are verified to be similar to the average of Californian banks.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1713-1719
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• 2014

1FSD is a 28-residue designed protein with a ${\beta}{\beta}{\alpha}$ motif. Since this protein displays most essential features of protein structures in such a small size, this model protein can be an outstanding system for evaluating the balance in the propensity of the secondary structures and the quality of all-atom protein force fields. Particularly, this protein would be difficult to fold to its correct native structure without establishing proper balances between the secondary structure elements in all-atom energy functions. In this work, a series of the recently optimized five amber protein force fields [$ff03^*$, $f99sb^*$-ildn, ff99sb-${\phi}^{\prime}$-ildn, ff99sb-nmr1-ildn, ff99sb-${\Phi}{\Psi}$(G24, CS)-ildn] were investigated for the simulations of 1FSD using a conventional molecular dynamics (MD) and a biased-exchange meta-dynamics (BEMD) methods. Among those tested force fields, we found that ff99sb-nmr1-ildn and ff99sb-${\Phi}{\Psi}$(G24, CS)-ildn are promising in that both force fields can locate the native state of 1FSD with a high accuracy (backbone rmsd ${\leq}1.7{\AA}$) in the global free energy minimum basin with a reasonable energetics conforming to a previous circular dichroism (CD) experiment. Furthermore, both force fields led to a common set of two distinct folding pathways with a heterogeneous nature of the transition state to the folding. We anticipate that these force fields are reasonably well balanced, thereby transferable to many other protein folds.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1565-1570
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• 2020

Photons with the energy of 60 keV are regularly used for some kinds of bone density examination devices, like the single photon absorptiometry (SPA). This article reports a flexible and lightweight rare earth/polymer composite for enhancing shielding efficiency against photon radiation with the energy of 60 keV. Lead oxide (PbO) and several rare earth element oxides (La₂O₃, Ce₂O₃, Nd₂O₃) were dispersed into natural rubber (NR) and the photon radiation shielding performance of the composites were assessed using monte carlo simulation method. For 60 keV photons, the shielding efficiency of rare earthbased composites were found to be much higher than that of the traditional lead-based composite, which has bad absorbing ability for photons with energies between 40 keV and 88 keV. In comparison with the lead oxide based composite, Nd₂O₃-NR composite with the same protection standard (the lead equivalent is 0.25 mmPb, 0.35 mmPb and 0.5 mmPb, respectively), can reduce the thickness by 35.29%, 37.5% and 38.24%, and reduce the weight by 38.91%, 40.99% and 41.69%, respectively. Thus, a flexible, lightweight and lead-free rare earth/NR composite could be designed, offering efficient photon radiation protection for the users of the single photon absorptiometry (SPA) with certain energy of 60 keV.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.6
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• pp.735-746
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• 1999

We design the robust and inherently fault tolerant decetralized$$H^infty$$ filter for the multisensor state estimation problem when there are insufficient priori informations on the statistical properties of external disturbances. For developing the proposed algorithm, an alternative form of suboptimal$$H^infty$$ filter equations are formulated by applying an alternative form of Kalman filter equations to the indefinite inner product space state model of suboptimal$$H^infty$$ filtering problems. The decentralized$$H^infty$$ filter that consists of local and central fusion filters can be designed effciently using the proposed alternative$$H^infty$$ filiter gain equations. The proposed decentralized$$H^infty$$ filter is robust against un-known external disturbances since it bounds the maximum energy gain from the external disturbances to the estimation errors under the prescribed level$$r^2$$ in both local and central fusion filters and is also fault tolerant due to its inherent redundancy. In addition, the central fusion equations between the global and local data can reduce the unnecessary calculation burden effectively. Computer simulations are made to ceritfy the robustness and fault tolerance of the proposed algorithm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.9 no.1
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• pp.1-15
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• 2003

A recent trend of global shipping industry adopting Port State Control (PSC) system is recognized as a proficient mechanism in preventing maritime accident and protecting marine environment. Disadvantages of Korean shipping companies in PSC inspection are unavoidable as Tokyo MOU imposed priority listed flag to Korea Having stated above, appropriate research and prompt preparation in compliance with current PSC requirements for the Korean shipping companies have become an immediate need The objectives of this study are: First, to review in understanding of PSC in overall and foundation of enforcement. Second, to study interaction of international treaties regarding PSC. Third, to compare practical compliance among the countries and to open up a case study on Korean shipping companies in adopting PSC Last, to suggest direction to the Korea shipping companies the most proficient way in compliance with the current Tokyo MOU requirement.

• Journal of Ocean Engineering and Technology
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• v.32 no.3
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• pp.184-191
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• 2018

Recently, as sea ice in the Arctic has been decreasing due to global warming, it has become easier to develop oil and gas resources buried in the Arctic region. As a result, Russia, the United States, and other Arctic coastal states are increasingly interested in the development of oil and gas resources, and the demand for offshore structures to support Arctic sea resources development is expected to significantly increase. Since offshore structures operating in Arctic regions need to secure safety against various drifting ice conditions, the concept of an ice-strengthened design is introduced here, with a priority on calculation of ice load. Although research on the estimation of ice load has been carried out all over the world, most ice-load studies have been limited to estimating the ice load of the icebreaker in a non-oblique state. Meanwhile, in the case of Arctic offshore structures, although it is also necessary to estimate the ice load according to oblique angles, the overall research on this topic is insufficient. In this paper, we suggest algorithms for calculating the ice load of managed ice (pack ice, 100% concentration) in an oblique state, and discuss validity. The effect of oblique angle according to estimated ice load with various oblique angles was also analyzed, along with the impact of ship speed and ice thickness on ice load.