• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.11
• /
• pp.112-119
• /
• 1999

TMN5 has been used to evaluate the performance of H.263, the ITU-T/LBC standard of moving picture coding. As DCT is used as transform coding methods in TMN5, blocking effect exists seriously in reconstruction picture at low bit rate. In this pater, DWT is substituted for DCT and adaptive quantizer is designed while the structure of TMN5 is maintained to be excellent in the transplantation of conventional system. It has shown that average PSNR is reduced by 0.35dB in luminance but increased by 2dB in chrominance comparing with that of TMN5. As block effect is reduced in reconstruction picture, the subjective picture quality is better than that of TMN5. Picture drop is, also, reduced because much more frames are transmitted at same bit rate.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.3 s.19
• /
• pp.128-136
• /
• 2004

Since the Construction Management(CM) was introduced into the Korea construction industry, the efforts for acceleration of CM adaption have been continued. The fact that an owner organization has the essential key to successful application of CM delivery method is true, but there has been no study on owner's organization. An owner should decide their organization type and measure their current needs for several different construction business functions for successful application of CM. After the needs of CM business functions are measured, the owner should reinforce their required business functions through strengthening their in-house capability or outsourcing. Thus, this paper defines four kinds of owner organization type and suggest the form for evaluation of owner's CM ability and analyze about needs of each type's CM capability through a survey.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.10
• /
• pp.1291-1296
• /
• 2013

Risk-based inspection (RBI) is a well-known method that is used to optimize inspection activities based on risk analysis in order to identify the high-risk components of major facilities such as power plants. RBI, when implemented and maintained properly, improves plant reliability and safety while reducing unplanned outages and repair costs. Risk is given by the product of the probability of failure (POF) and the consequence of failure (COF). A semi-quantitative method is generally used for risk assessment. Semi-quantitative risk assessment complements the low accuracy of qualitative risk assessment and the high expense and long calculation time of quantitative risk assessment. The first step of RBI is to identify important failure modes and causes in the equipment. Once these are defined, the POF and COF can be assessed for each failure. During POF and COF assessment, an effective inspection method and range can be easily found. In this paper, the calculation of the POF is improved for accurate risk assessment. A modified semi-quantitative risk assessment was carried out for boiler facilities of thermal power plants, and the next maintenance schedules for the equipment were decided.

• Journal of the Korean Chemical Society
• /
• v.37 no.8
• /
• pp.702-710
• /
• 1993

Electrochemical reduction of thionyl chloride has been carried out at glassy carbon and molybdenum electrodes, the surface of which is modified by binuclear tetradentate schiff base Co(II), Ni(II),Cu(II) and Fe(II) complexes. The catalyst molecules of transition metal(II) complexes were adsorbed on the electrode surface and reduced thionyl chloride resulting in a generation of oxidized catalyst molecules. There was an optimum concentration for each catalyst compound. The catalytic effects of SOCl$_2$ reduction were larger on glassy carbon electrodes compared to molybdenum electrodes and enhancements in reduction current of up to 120${\%}$ at the glassy carbon electrodes. The reduction currents of thionyl chloride were increased and the reduction potentials were shifted to the negative potential when scan rates became faster. The reduction of thionyl chloride was proceed to diffusion controlled reaction.

• Magazine of the Korea Concrete Institute
• /
• v.8 no.5
• /
• pp.123-133
• /
• 1996

Recently, the construction of infrastructures has been booming and accelerating to keep up with rapid economic growth. Construction activities and operation of transportation facilities cause unfavorable effects such as civil petitions associated with vibration-induced damages or nuisances. Accordingly, the objective of this study is to develop vibration-controlled concrete using various vibration-controlled mixtures, and also to recycle obsolete materials in part. As the first step to achieve this research, preliminary mix designs have been carried out to obtain an appropriate mix proportion above 200kg/$\textrm{cm}^2$ in uniaxial compressive strength. Test specimen based on the mix proportion selected have been actuated by the impact hammer to investigate their dynamic characteristics. Vibration-controlled mixtures are foam, latex, rubber powder and plastic resin, which have been determined to reduce a vibration by and large. KS F2437 and travel time method have been used to figure out 1st natural frequency and dynamic elastic moduli. Damping ratios have been computed by adopting the polynomial curvefitting method and the geometric analysis method on the frequency response spectrum curve. of which results have been compared and analyzed hereon.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.5
• /
• pp.1057-1063
• /
• 2010

Development of e-navigation strategy which was proposed by seven member states coordinated by United Kingdom in MSC committee of IMO has been conducted for user needs definition, gap analysis cooperating with NAV, COMSAR and STW sub-committee. After prominent progress of development was done in Correspondence group, MSC 85 has approved the result of the group and conducted the development of e-navigation implementation plan to be finished in 2012. It is necessary to prepare the strategy and plan of our country identifying and perceiving the core objects and basic concept of e-navigation developed in the international community. This paper presents the progress of e-navigation development work until this stage and gives some recommendations for the domestic plan to cope with e-navigation.

• Journal of Practical Engineering Education
• /
• v.14 no.3
• /
• pp.471-477
• /
• 2022

In this study, an educational program was developed that allows students who take data science courses in the high school credit system to explore related fields after learning data science education. Accordingly, the existing research and requirements for data science education were analyzed, a learning plan was designed, and an educational program was developed in accordance with a step-by-step educational program. In addition, since there is no research on data science education for the high school credit system in existing studies, the research was conducted in the stages of problem definition, data collection, data preprocessing, data analysis, data visualization, and simulation, and referred to studies on data science education that have been conducted in existing schools. Through this study, it is expected that research on data science education in the high school credit system will become more active.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.22 no.1
• /
• pp.83-109
• /
• 1977

Isogenic lines for glabrous leaf (gl), hull color(gh) and glutinous endosperm (wx) were used to clarify the effects of the gl, gh and wx gene on the grain yield and yield components in rice plant. Eight genotypes: glgl ghgh wxwx, glgl ghgh WxWx, glgl GH-wxwx, glgl GH-WxWx, GL-ghgh wxwx, GL-ghgh WxWx, GL-GH-wxwx and GL-GH-WxWx were evalutated in the backcrossed $F_2$ generation. Significant effects were measured for gl genotypes on heading date, gh genotypes on grain fertility, and wxwx genotypes on number of panicles per hill and 1, 000 grain weight. The grain yield of straw hull and non glutinous lines were higher than gold hull and glutinous lines. The interaction of three genes, gl, gh and wx was significant for heading date, but not significant in other characters. The average value of isogenic lines which were combined with two recessive genes and one dominant gene were lower and the C.V. value was higher than the isogenic lines which were combined with two dominant genes and one recessive gene in all characters except plant height and number of grains per plant. The average value of isogenic line combined with three recessive genes was lower and the C.V. was higher than the isogenic line combined three dominant genes in all characters measured.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.2
• /
• pp.129-137
• /
• 2014

In this study, the characteristics of exhaust gas as a function of the biodiesel mixing ratio were investigated. Diesel and waste oil were used for preparing mixed fuel, and the ratios of the mixed fuel were varied in the BD3~BD100 range. The injection pressures(${\Delta}p_{inj}$) was considered as an experimental variable and was set to 400 bar, 600 bar, 800 bar, 1000 bar, and 1200 bar. Furthermore, for quantitatively analyzing the characteristics of exhaust gas(NOx and Soot), the concepts of Pearson correlation coefficient and Spearman rank-order correlation coefficient based on statistics were introduced. Consequently, it was found that the correlation of the emission of NOx and Soot is linear, and the Pearson and Spearman coefficients are -0.732 and -0.724, respectively, under all analysis conditions. Especially, for the injection pressure of 800 bar, a simultaneous reduction in NOx and Soot emission is possible by controlling the biodiesel mixing ratio. This is because the correlation coefficients of NOx and Soot emissions were nearly 0, as the Pearson correlation coefficient was -0.089.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.1
• /
• pp.59-66
• /
• 2016

Pollution contribution rate that is effect on water quality from land based load in Masan bay was showed quantifiably for coastal water quality management by using ecological model. It was calculated by difference of water quality concentration at each points t hat is calculated by each scenarios that are presence or absence of each sources (16 points). Results show that, rivers of Northern Masan bay contributed in Masan bay COD is 20 %, T-P is 62 % at northern part and COD is 10 %, T-P is 16 % at middle part. As a result, rivers of Northern Masan bay had effect on water quality of northern Masan bay and middle Masan bay. Also, T-P load affects water quality bigger than COD load, because T-P contribution rate bigger than COD contribution rate of northern rivers. Dukdong WTTP that is land pollution source of southern Masan bay contributed in Masan bay COD is 26 %, T-P is 11% at middle part, COD is 17 %, T-P is 7 % at middle part and COD is 10 %, T-P is 1 % at outer part. It affects water quality bigger at southern and middle of Masan bay than outer bay, because residual flow of bottom flows toward inner of Masan bay nearby Dukdong WTTP.