Kang Y.K.,Chungbuk National University |
Park H.S.,Halla University
Chemical Physics Letters | Year: 2014
The CCSD(T), MP2, dispersion-corrected DFT, CBS-QB3, and G4(MP2) levels of theory with various basis sets are assessed for their ability to describe the conformational preferences of the Ala and Pro dipeptides. The ωB97X-D/6-311++G(d,p) level of theory provided the rotational constants of the most stable conformer of the Ala dipeptide consistent with the values from microwave experiments. The double-hybrid DSD-PBEP86-D3BJ DFT method provided the best performance for relative energies of both dipeptides consistent with CCSD(T)/CBS limit values. The DSD-PBEP86-D3BJ/cc-pVTZ//M06-2X/6-31+G(d), B2PLYPD-D3BJ/cc-pVTZ//M06-2X/6-31+G(d), and M06-2X/cc-pVTZ//M06-2X/6-31+G(d) levels of theory may be an alternative to the CCSD(T)/CBS limit//ωB97X-D/ 6-311++G(d,p) level of theory with marginal deviations for conformational study of peptides. © 2014 Elsevier B.V. All rights reserved.
Yu B.,Inha University |
Kum S.-M.,Halla University |
Lee C.-E.,Inha University |
Lee S.,Inha University
Energy | Year: 2013
This research was conducted to experimentally compare the emission characteristics and thermal efficiency of porous-media types of burners and to determine which types to use with a condensing boiler to be developed later. Three types of porous-media burners; metal fiber (MF), ceramic (CM) and stainless steel fin (SF) were used with a commercial heat exchanger and tested for various equivalence ratios and burner capacities. The MF burner had the lowest CO emissions of the three burner types, and the SF burner had the highest CO emissions. However, The MF burner had the highest NOx emission and thermal efficiency, and the SF burner had the lowest NOx emissions and thermal efficiency. In other words, the smaller the burner porosity was (porosity: SF < CM < MF), the higher the CO emission was and the lower the thermal efficiency was. Based on the thermal efficiency, turn-down ratio and NOx and CO emissions with respect to the Korean industrial standard and European norms, the most appropriate burner type for the condensing boiler is the MF burner. The optimal operating equivalence ratio was 0.80 for the range of experimental factors considered in this research. © 2013 Elsevier Ltd.
Lee E.J.,Halla University |
Bukowski W.M.,Concordia University at Montréal
Journal of Adolescence | Year: 2012
Latent growth curve modeling was used to study the co-development of internalizing and externalizing problems in a sample of 2844 Korean fourth graders followed over four years. The project integrated two major theoretical viewpoints positing developmental mechanism: directional model and common vulnerability model. Findings suggest that (a) boys and girls follow different developmental trajectories in both domains in early adolescence; (b) bidirectional progression from initial levels of each domain to the developmental pattern of the other domain emerged among boys, while only unidirectional progression from externalizing to internalizing problem emerged among girls; and (c) all risk factors are not equally risky across domain and gender; parental violence was a common cross-domain risk factor for boys, whereas affiliation with delinquent friends was a common cross-domain risk factor for girls. Implications for future research and intervention were discussed. © 2011 The Foundation for Professionals in Services for Adolescents.
Kim S.S.,Halla University
Journal of Supercomputing | Year: 2016
This study suggested a new security method which can be applied to healthcare environment aimed at those geographically living away from hospitals, including the elderly living alone, the handicapped, people living in islands and highlands, and chronic disease patients. In other words, it proposed a new authentication scheme of exchanging safely information between personal health device (PHD) to measure the bio-information of a chronic disease patient at home and data manager (DM) to collect the bio-information from the device. In terms of operations, the proposed scheme features the generation of a random number once by PHD and DM, respectively, two times of XOR operation, and one time of encoding and decoding operation. Therefore, given the low-power characteristic of PHD, it is very efficient. In addition, since a random number is used for encoding and decoding operation, the data to be transmitted is not only variable, but safe from illegal third parties’ attacks, including eavesdropping, location-tracking, spoofing, and replay. In particular, the proposed scheme can be applied directly to ISO/IEEE 11073-20601 standard. Therefore, it is judged that the proposed authentication scheme is very useful in the point that it added the mutual authentication function to PHD and DM to implement safer and more efficient e-health environment. © 2015, Springer Science+Business Media New York.
Kim E.-S.,Halla University
Journal of Electrical Engineering and Technology | Year: 2012
In this paper, the observer based nonlinear state feedback controller has been developed to control the pressures of the oxygen and the hydrogen in the PEM(Proton Exchange Membrane) fuel cell system. Nonlinear model of the PEM fuel cell system was introduced to study the design problems of the state observer and model based controller. A cascade observer using the filtering technique was used to estimate the pressure derivatives of the cathode and the anode in the system. In order to estimate the pressures of the cathode and the anode, the sliding mode observer was designed by using these pressure derivatives. To estimate the oxygen pressure and the hydrogen pressure in the system, the nonlinear state observer was designed by using the cathode pressure estimates and the anode it. These results will be very useful to design the state feedback controller. The validity of the proposed observers and the controller has been investigated by using the Lyapunov's stability analysis strategy.
Oh J.,Halla University |
Hwang H.,Halla University
International Journal of Control, Automation and Systems | Year: 2010
In this paper, we present a new morphology-based homomorphic filtering technique for feature enhancement in medical images. The proposed method is based on decomposing an image into morphological subbands. The homomorphic filtering is performed using the morphological subbands. The differential evolution algorithm is applied to find an optimal gain and structuring element for each subband. Simulations show that the proposed filter improves the contrast of the features in medical images. © 2010 ICROS, KIEE and Springer.
Yoo Y.K.,Halla University
International Journal of Systems Science | Year: 2011
This article presents some operating characteristics of a failure counting group replacement policy. A group of identical units are put in service together. The maintenance policy applied for them is a group replacement policy based on failure count; they are replaced altogether when a number of failures reaches a certain amount. For the expected cost rate function under the failure counting group replacement policy, this article presents a method to obtain the optimum cost rate. We also show that the optimum cost rate is an increasing function in the fleet size. Numerical examples are presented to demonstrate the results. © 2011 Taylor & Francis.
Halla University | Date: 2012-08-14
Provided are a method of generating a forward error correction (FEC) packet for scalable video streaming and a server and a client apparatus using the same. The method includes generating a plurality of temporal layers (TLs) of which the number is a second number to provide temporal scalability for one group of pictures (GOP) constituted of a plurality of frames of which the number is a first number, allocating FEC data to the TL, and generating a transmission packet by interleaving at least one of the FEC data and video data constituted of at least one frame for the TL. FEC can be performed without receiving all data by allocating FEC data in units of TLs, and hence a delay can be minimized. In addition, there is an advantage in that robustness to burst errors is provided by applying interleaving between video data and FEC data for the TLs.
Sur U.,Halla University
Nuclear Engineering and Technology | Year: 2011
This paper is a study on a nuclear water chiller. It presents a test-verified finite element model of a water chiller to be used at a Nuclear Power Plant. The test-verified model predicts natural frequencies within 5% for all major modes below 50 Hz. This model accurately represents the dynamic characteristics of the actual hardware and is qualified for its use in the final stress analysis for seismic verification.
Senay S.,University of Pittsburgh |
Oh J.,Halla University |
Chaparro L.F.,University of Pittsburgh
Signal Processing | Year: 2012
In this paper, we propose a method for efficient signal reconstruction from non-uniformly spaced samples collected using level-crossing sampling. Level-crossing (LC) sampling captures samples whenever the signal crosses predetermined quantization levels. Thus the LC sampling is a signal-dependent, non-uniform sampling method. Without restriction on the distribution of the sampling times, the signal reconstruction from non-uniform samples becomes ill-posed. Finite-support and nearly band-limited signals are well approximated in a low-dimensional subspace with prolate spheroidal wave functions (PSWF) also known as Slepian functions. These functions have finite support in time and maximum energy concentration within a given bandwidth and as such are very appropriate to obtain a projection of those signals. However, depending on the LC quantization levels, whenever the LC samples are highly non-uniformly spaced obtaining the projection coefficients requires a Tikhonov regularized Slepian reconstruction. The performance of the proposed method is illustrated using smooth, bursty and chirp signals. Our reconstruction results compare favorably with reconstruction from LC-sampled signals using compressive sampling techniques. © 2011 Elsevier B.V. All rights reserved.