Distribution and sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the glacimarine sediments (35 sites) of Svalbard were investigated. PCBs (32 congeners), traditional PAHs (15 homologs), emerging PAHs (11 homologs), and alkylated PAHs (16 homologs) were widely distributed in the Svalbard sediments (ranges: below method detection limit to 20, 21 to 3600, 1.0 to 1400, and 31 to 15,000 ng g-1 dry weight, respectively). Compositional analysis indicated that PCBs mainly originated from combustion sources, with PAHs being strongly influenced by local sources. Positive matrix factorization analysis showed that PAHs were associated with vehicle and petroleum combustion, coal, and coal combustion. Coal-derived PAHs contributed significantly to the sediments of Van Mijenfjorden. Remnants of coal mining activity trapped in the permafrost appear to enter the coastal environments as ground ice melts. Consequently, PAHs are currently emerging as the most significant contributors to potential risks in the Svalbard ecosystems.

Based on long-term AERONET observations in the Korean peninsula, we evaluate how well the Ångström exponent (AE) can describe the regional aerosol size well in comparison to the fine mode fraction (FMF). Despite close relationships between AE and FMF previously reported, we found that AE is not always linearly correlated to the FMF in the Korean peninsula, particularly during the summertime. Seasonal patterns of volume size distribution indicate that the volume median and peak radius of the fine mode are obviously enhanced in the summer. Since the ambient conditions in Korean summer are highly humid, cloudy, and stagnant, the size of regional fine mode aerosol can increase significantly due to hygroscopic growth and/or cloud processing in this highly polluted atmosphere. In contrast to the AE, the AE ratio (AE at longer wavelengths divided by AE at shorter wavelengths; AER) correlates better with the FMF variation in summer, but a little worse in the spring. This suggests that the combined consideration of AE and AER may provide a better characterization relative to FMF. Thus, we try to estimate the FMF based on the multiple linear regression method using both AE and AER. As expected, the estimated FMF shows remarkably high linear correlations with the AERONET FMF without any seasonal bias. These findings imply that the FMF in South Korea can be simply obtained if just the AOT measurement at multiple wavelengths (in the range from ultraviolet to near-infrared channels) are available.

To investigate the consistency and difference between AERONET version 2 and 3 data set in the Korean peninsula, we compared several aerosol optical properties for 12 Korean AERONET sites having at least 2-year measurement records. Generally, both version products have similar patterns, but we sometimes found a little regional difference. While the aerosol optical depth (AOD) is analogous between version 2 and 3, the version difference of single scattering albedo (SSA) is the largest. Ångström exponent (AE) and fine mode fraction (FMF) values are sometimes different in maritime conditions. Two AERONET sites in Seoul (Seoul_SNU and Yonsei_Univ) have some differences between version 2 and 3, probably related to the higher sensitivity of version 3 data to the fine mode particle. Since parameters revealing the aerosol radiative property (e.g., SSA) and size information (e.g., AE and FMF) show some version differences regionally, we compared the result of aerosol type classification using these parameters. As a result, we found that the version difference of aerosol size and radiative property can induce the different diagnosis of locally dominant aerosol types. In spite of these findings, consistency between version 2 and 3 is quite large. Thus, regional patterns of aerosol optical properties previously found based on AERONET version 2 look still valid in the Korean peninsula.

Recently, as the existing lighting infrastructures are replaced by LED lighting, optical camera communication (OCC) technology in vehicle-infrastructure communication (V2I) systems have been actively researched. In this paper, we introduce a method to improve data packet reception rate of OCC-based V2I by using deep learning based region-of-interest (ROI) detector. In the V2I environment, traffic lights on the roadside are ROIs that perform as transmitters sending OCC data, and should be detected at the receiving camera. If ROI detectors utilize a deep learning model, data can be extracted stably during actual driving. From the experiment result, it was found that data packet reception rate using deep-learning based ROI detection technique outperforms that of conventional method based on image differentiation.

In numerical analysis of heat transfer including complicated computational domains or geometries, the domains are divided into several simple domains, and it is possible to generate cells in the simple domains easily. However, for the sake of the isolation of the domains, the methods lead the vertex mismatch between the divided regions, and become non-conformal. Because of the non-conformal meshes, it is difficult to calculate fluxes through the interface. Therefore, a computational treatment for the non-conformal mesh is required to obtain geometrical information between neighboring cells. A clipping method to find the geometrical information are developed, and applied to thermal conduction problems. The clipping method implemented in this study is advantageous in using simple vector operations only to obtain the geometrical information on the non-conformal interface. To test the accuracy of the clipping method, twelve cases with different grid configurations are presented. They show that the method has a high degree of accuracy for calculating the clipped areas. Furthermore, to validate the scheme, the heat conduction problem is performed. And then, the numerical result agrees well with the exact solution. Additionally, we apply the scheme to the fourth case in the ISO 10211 that includes two materials with different aspect ratios. In the vicinity of the interface, the high temperature gradients are presented because of the different thermal conduction coefficients. Therefore, it shows that the present methods can treat the non-conformal meshes with the different neighboring cell size properly.

Initial performance of the UltraLo-1800 alpha particle detector at the 700 m deep Yangyang underground laboratory in Korea is described. The ionization detector uses Argon as a counting gas for measuring alpha events of a sample. We present initial calibration results and low-activity sample measurements based on the detector's pulse discrimination method and a hardware veto. A likelihood analysis that shows a separation of a bulk component from a surface component with a contamination depth from 210Po alpha particles using simulated models is presented.

Recently, security issues have become more and more important to apply machine learning models to a real-world problem. It is necessary to preserve the data privacy for using sensitive data and to protect the information of a trained model for defending the intentional attacks. In this paper, we want to propose a security-preserving learning framework using fully homomorphic encryption for support vector machine model. Our approach aims to train the model on encrypted domain to preserve data and model privacy with the reduced communication between the servers. The proposed procedure includes our protocol, data structure and homomorphic evaluation. As machine learning models have been effectively applied to various real-world problems, collecting data from various sources became crucial for many service providers(Park, Hah, and Lee 2017). In this situation, privacy issues have become a major problem in the learning society. Therefore, it is necessary to preserve the privacy of the data and the security of the learning process without compromising the performance of the learning algorithms. Homomorphic encryption (HE) enables computations on encrypted data (ciphertext) which are equivalent to operations on decrypted data (plaintext) (Gentry 2009). In recent years, privacy-preserving machine learning applications have developed, but they have high computational cost and huge memory burden. Cheon et al. developed a homomorphic encryption scheme for approximate arithmetic (HEAAN) (Cheon et al. 2017). Support vector machine (SVM) is one of the most effective machine learning algorithms for classification (Cortes and Vapnik 1995). The training data and the model parameters should be protected to apply the SVM model to the security-preserving scenario. Therefore, in this paper, we propose the implementation for the training phase of the SVM classifier on the encrypted domain with the HEAAN scheme.

Wing-in-ground (WIG) effect vehicles skim the surface of the ground or water using an air cushion between the vehicle and the surface. The lift augmentation and drag reduction are considerable compared to an airplane flying out of ground effect and significantly enhance the aerodynamic performance. However, the stability problem is still a challenge for researchers and designers of WIG effect vehicles. In a previous study, sectional shapes were optimized for the wing-in-round effect (WIG) using computational fluid dynamics (CFD) and multi-objective optimization with two objectives: the aerodynamic center of height, which is part of the static height stability, and the lift-to-drag ratio. The optimization study obtained 113 optimal solutions called Pareto optima or Pareto sets, which include various airfoil profiles such as a flat lower surface and a convex lower surface next to the trailing edge. In this study, some of the Pareto optima that show the characteristics of features in the design domain are selected, and are applied to a three-dimensional vehicle with a fuselage, lifting and control surfaces such as a horizontal tail. Three featured optima that show high stability, high performance, and relatively stable cases are carefully investigated using computational methods to analyze the aerodynamic characteristics, stability, and three-dimensional effects.

In recent years, BLDC motors have been used in various fields, because they are more reliable and efficient than conventional DC motors. In this paper, the hollow shaft BLDC motor is proposed for increasing the flow efficiency of the fluid for a fan blower. As the result of fluid analysis with the BLDC motor for fan blower, the energy efficiency of fluid transfer with the hollow shaft BLDC motor was increased compared with the conventional shaft BLDC motor.

Purpose: As the importance of ecological architecture such as prevention of condensation, thermal analysis with numerical methods became essential in a modern architecture. A grid-based numerical method is widely used, and various grid shapes have been studied. Notably, an unstructured grid has been attracted by means of successful results. Due to the its flexibility of an unstructured grid, it is possible to divide a complex domain into several simple domains in which the grid are generated easily and independently. However, the grid points on the interface between neighbor domains are not matched completely so called non-conformal grid, and thus, the flux between neighbor cells cannot calculate directly. Thus, a technical treatment for the arbitrary interface is required. Method: We employed the clipping method that calculates the connectivity and geometrical information between non-conformal cells on the interface. To validate the clipping method, the heat conduction with a non-conformal interface was performed. Result: The algorithm that we developed represented the interface, and the numerical result agreed with the analytic solution for a heat conduction problem.

The simultaneous measurement of heat and light signals from a (CaMoO4)-Ca-40-Mo-100 scintillating crystal was performed at temperatures of tens of milli-kelvin using a scintillating bolometric detector. The crystal was instrumented with a pair of low-temperature detectors, consisting of a metallic magnetic calorimeter for reading the phonon signals and a light detector based on a Ge light absorber, to simultaneously measure the scintillation light and phonon signals. This article presents the principle and performance, such as the event separation capability, of this simultaneous heat/light measurement system.

Three-dimensional unsteady numerical analysis has been performed to observe aerodynamic characteristics of a H-rotor. Generally, the structure of the H-rotor is simple but the aerodynamic characteristics are exceptionably complicated since the angle of attacks and incident velocities to a blade are considerably varied according to the azimuth angles and solidities. The blade in the upwind revolution between 0 to 180 degree obtains aerodynamic energy from the free stream but the blade in the downwind revolution between 180 to 360 degree does not. When the rotating speed increases, the blade in the downwind revolution accelerates the air around the blade like a fan and it consumes the energy and shows negative torque in the area. On the other hand, the direction of the free stream is bent because of the interaction between blade the free stream. Therefore, the operation point (highest power coefficient) appears at a lower tip-speed-ratio what it is expected.

The heat conduction equation, a type of a Poisson equation which can be applied in various areas of engineering is calculating its value with the iteration method in general. The equation which had difference discretization of the heat conduction equation is the simultaneous equation, and each line has the characteristic of expressing in sparse matrix of the equivalent number of none-zero elements with neighboring grids. In this paper, we propose a data structure for sparse matrix that can calculate the value faster with less memory use calculate the heat conduction equation. To verify whether the proposed data structure efficiently calculates the value compared to the other sparse matrix representations, we apply the representative iteration method, CG (Conjugate Gradient), and presents experiment results of time consumed to get values, calculation time of each step and relevant time consumption ratio, and memory usage amount. The results of this experiment could be used to estimate main elements of calculating the value of the general heat conduction equation, such as time consumed, the memory usage amount.

This paper examines the loanword adaptation pattern of Russian obsturents in Korean. We observe the loan adaptation patterns of Russian in the Seonbong newspaper (published between 1922 and 1937) in Yeonhaeju (Primorskij Kraj). Based on the collected data, we first provide an extensive analysis on the loan adaptation of Russian obstruents into Korean and show the general loan adaptation pattern. We then focus on the adaptation pattern of the Russian /v/ showing the 〈p〉~〈ph〉~〈w〉 alternation. To investigate the mysterious variation, we conduct a perception test with 24 real Russian words in various phonological environments. The experimental result indicates that the variation is sensitive to the syllable position. Moreover, it resolves earlier controversy on the nature of the Russian /v/ (Avanesov 1956, Hayes 1984, Padgett 2002), showing that the Russian /v/ is phonetically [+sonorant].

A transmission electron microscopy investigation on the phase decomposition of B2-ordered (Ni,Co)Al supersaturated with Ni and Co has revealed the precipitation of (Ni,Co)2Al which has not been expected from the reported equilibrium phase diagram. The (Ni,Co)2Al phase has a hexagonal structure and takes a rodlike shape with the long axis of the rod parallel to the 〈111〉 directions of the B2 matrix. By aging at temperatures below 873 K, a long period superlattice structure appears in the hexagonal (Ni,Co)2Al phase. The orientation relationship between the (Ni,Co)2Al precipitates and the B2-(Ni,Co)Al matrix is found to be (0001)p//(111)B2 and [\(\bar 1\)2\(\bar 1\)0]p//[\(\bar 1\)10]B2, where the suffix p and B2 denote the (Ni,Co)2Al precipitate and the B2-(Ni,Co)Al matrix, respectively. (Ni,Co)Al hardens appreciably by the fine precipitation of the (Ni,Co)2Al phase.

This paper describes the development of the Korean corpus of spontaneous speech, also called the Seoul corpus. The corpus contains the audio recording of the interview-style spontaneous speech from the 40 native speakers of Seoul Korean. The talkers are divided into four age groups; talkers in their teens, twenties, thirties and forties. Each age group has ten talkers, five males and five females. The method used to elicit and record the speech is described. The corpus containing around 220,000 phrasal words was phonemically labeled along with information on the boundaries for Korean phrasal words and utterances, which were additionally romanized. According to the test result of labeling consistency, the inter-labeler agreement on phoneme identification was 98.1% and the mean deviation on boundary placement was 9.04 msec. The corpus will be made available for free to the research community in March, 2015.

Three-dimensional unsteady numerical analysis has been performed in order to analyze the aerodynamic characteristics of an H-Darrieus vertical axis wind turbine with two straight blades. The reliability of the numerical models has been demonstrated through good agreement between the calculated and measured efficiency of an H-Darrieus. Flow characteristics are closely investigated according to tip speed ratios and solidities. A comparison of aerodynamic characteristics at various operational conditions, including the maximum power point is performed. The direction of the free stream approaching the blade is considerably bent following the interaction between blade-to-blade and blade-to-free stream. Even though, the peak value of a torque increases as solidity increases, the blockage and interaction also increase, and thus, increasing the solidity alone does not improve the performance of the H-Darrieus. On the other hand, decreasing the solidity can reduce the effect of blockage and interaction, but the self-starting features via the negative torque at the low tip speed ratio becomes lost. Therefore, a theoretical model such as the DMST (double multiple stream tube) is not suitable for predicting the performance of H-Darrieus with a high solidity. The blockage by blades in the upwind revolution and the interaction between blades significantly change the magnitude of an incidence velocity, and the angle of attack. Thus, the tip speed ratio of the operation point (i.e. the highest power coefficient point) is found to be lower than it is expected.

No AccessEngineering NoteAerodynamic Characteristics of a Rectangular Wing in Ground ProximitySanghwan Lee and Juhee LeeSanghwan LeeMechanical Engineering, Hanyang University, Seoul 133-791, Republic of Korea*Professor, Mechanical Engineering, 222 Wangsimni-ro.Search for more papers by this author and Juhee LeeMechatronics Engineering, Hoseo University, Asan 336-795, Republic of Korea†Assistant Professor, Mechatronics Engineering. Member AIAA (Corresponding Author).Search for more papers by this authorPublished Online:3 Apr 2014https://doi.org/10.2514/1.C032327SectionsView Full TextPDFPDF Plus ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail About References [1] Rozhdestvensky K. V., “Wing-in-Ground Effect Vehicles,” Progress in Aerospace Sciences, Vol. 42, No. 3, 2006, pp. 211–283. doi:https://doi.org/10.1016/j.paerosci.2006.10.001 PAESD6 0376-0421 CrossrefGoogle Scholar[2] Zhang X. and Zerihan J., “Aerodynamics of a Double-Element Wing in Ground Effect,” AIAA Journal, Vol. 41, No. 3, 2003, pp. 1007–1016. doi:https://doi.org/10.2514/2.1972 AIAJAH 0001-1452 LinkGoogle Scholar[3] Phillips W. F., Mechanics of Flight, 2nd ed., Wiley, Hoboken, NJ, 2010, pp. 46–49. Google Scholar[4] Lee S. H. and Lee J. H., “Optimization of Three-Dimensional Wings in Ground Effect Using Multiobjective Genetic Algorithm,” Journal of Aircraft, Vol. 48, No. 5, 2011, pp. 1633–1645. doi:https://doi.org/10.2514/1.C031328 JAIRAM 0021-8669 LinkGoogle Scholar[5] STAR-CCM+ v4.02 Methodology, Computational Dynamics Co., London, 2006. Google Scholar[6] Jacobs E. N. and Sherman A., “Airfoil Section Characteristics as Affected by Variations of the Reynolds Number,” NACA TM-586, 1939. Google Scholar[7] Anderson J. D., Aircraft Performance and Design, McGraw–Hill, New York, 1999, Chap. 2. Google Scholar[8] Razenbach R. and Barlow J., “Two Dimensional Airfoil in Ground Effect, an Experimental and Computational Study,” Vehicle Design Issues: 1994 Motor Sports Engineering Conference, Vol. 1, 1994, pp. 241–249. Google Scholar[9] Lee J., “Aerodynamic Characteristics of Rectangular Wing with Square Lateral Tip,” 51st AIAA Aerospace Sciences Meeting, AIAA Paper 2013-0250, Jan. 2013. Google Scholar[10] Lee J., Han C. and Bae C., “Influence of Wing Configurations on Aerodynamic Characteristics of Wings in Ground Effect,” Journal of Aircraft, Vol. 47, No. 3. 2010, pp. 1030–1040. doi:https://doi.org/10.2514/1.46703 JAIRAM 0021-8669 LinkGoogle Scholar[11] Anusongti-Inthra P. and Floros M., “Coupled CFD and Particle Vortex Transport Method: Wing Performance and Wake Validations,” 38th Fluid Dynamics Conference and Exhibit, AIAA Paper 2008-4177, June 2008. LinkGoogle Scholar[12] Zhang X. and Zerihan J., “Off-Surface Aerodynamic Measurements of a Wing in Ground Effect,” Journal of Aircraft, Vol. 40, No. 4, 2003, pp. 716–725. doi:https://doi.org/10.2514/2.3150 JAIRAM 0021-8669 LinkGoogle Scholar[13] Zhang X. and Zerihan J., “Edge Vortices of a Double-Element Wing in Ground Effect,” Journal of Aircraft, Vol. 41, No. 5, 2004, pp. 1127–1137. doi:https://doi.org/10.2514/1.1380 JAIRAM 0021-8669 LinkGoogle Scholar Previous article Next article