• The Korean Journal of Applied Statistics
• /
• v.27 no.3
• /
• pp.387-396
• /
• 2014

The GDP gap (also called the output gap) is the difference between potential GDP and actual GDP. Potential GDP is the maximum sustainable output that is achieved when the resources (labor and capital) are used to capacity. Central banks pursuing price and employment stability consider the output gap as an informative variable for monetary policy since the output gap could be regarded as a proxy of demand-supply imbalances. In this paper, the GDP gap of Korea is decomposed following the filtering method in the previous research, and major factors that affect the variation of GDP gap are investigated based on the decomposed series. The analysis results by the Super Smoother algorithm used in Fox et al. (2003)and Fox and Zurlinden (2006) are found consistent with theory. Much of the variation of nominal GDP gap is explained by Total Factor Productivity(TFP) gap, which is the change of productivity due to recent technological innovation and environmental change. It is also found that variation of terms of trade significantly affects the GDP gap of Korea due to its high dependency on international trade; however, the effect of the domestic price is not negligible like other countries.

• Journal of the korean society of oceanography
• /
• v.38 no.1
• /
• pp.1-10
• /
• 2003

A time-series sediment trap was deployed at a depth of 1034 m in the eastern Bransfield Strait from December 25, 1998 to December 24, 1999. Particle fluxes showed large seasonal variation; about 99% of the annual total mass flux (49 g m/sup -2/) was collected during the austral summer and fall (January-March). Settling particles consisted primarily of biogenic silica, organic carbon, calcium carbonate, and lithogenic material. Biogenic silica and lithogenic material predominated settling particles, comprising 36% and 30% of the total mass flux, respectively, followed by organic carbon, 11% and calcium carbonate, merely 0.6%. The annual organic carbon flux was 5.4 g C m/sup -2/ at 1000 m in the eastern Bransfield Strait, which is greater than the central Strait flux. The relatively lower flux of organic carbon in the central Bransfield Strait may be caused by a stronger surface current in this region. Organic carbon flux estimates in the eastern Bransfield Strait are the highest in the Southern Ocean, perhaps because of the fast sinking of fecal pellets, which leads to less decomposition of organic material in the water column. Approximately 5.8% of the organic carbon produced on the surface in the eastern Bransfield Strait is exported down to 1000 m; this percentage exceeds the maximum EF/sub 1000/ values observed in the Atlantic and Southern Oceans. The eastern Bransfield Strait appears to be the most important site of organic carbon export to the deep sea in the Southern Ocean.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.1
• /
• pp.173-188
• /
• 2002

In General, the measured loads and load-time function suggested by Bachmann iota walking are used for vibration analysis of structures subjected to footstep loads. It is not easy to measure walking loads because they we influenced by various parameters. Therefore, it is needed to model the walking loads that can be applied to structure analysis. Parameter study is used for the walking loads having various walking frequency for vibration analysis of structures under walking loads. In this study, walking loads were measured directly by using a force plate within two load cells, and the parameters of the walking loads were analyzed. The measured walking loads are decomposed into harmonic loads by using the Fouler series. Functional relationship between the walking frequency and the Fourier coefficients can be derived from the coefficients of harmonic loads obtained by the decomposition process, and the walking loads were formulated. It is possible to apply the venerated walking loads easily or conveniently by the proposed equation to the analysis of a structure subjected to walking loads.

• Journal of Korea Port Economic Association
• /
• v.23 no.4
• /
• pp.159-175
• /
• 2007

The purpose of this study is to examine the causal relationship between trading volume of freight and industrial growth in Korea ports, and to induce policy implications. In order to test whether time series data is stationary and the model is fitness or not, we put in operation unit root test, cointegration test. And we apply Granger causality based on an error correction model, Hsiao(1981) method and variance decomposition. The results indicate that the extent of causality between trading volume of freight and industrial growth is strong in order of Incheon port, Busan port, Gwang Yang port, Ulsan port. We can infer policy suggestions as follows; The port policy of government must be focused on re-adjusting investment among Korea ports and raising competitive power of Korea ports

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.7 no.4
• /
• pp.187-194
• /
• 1974

When rearing fish at recirculating filter systems, some pesticides are often used for controling various fish diseases. In this case, the pesticides are usually applied after stopping the filteration, from a view point of affecting the filtering ability of oxidation and decomposition by killing the decomposing bacteria in the filter system. Therefore, a great inconvenience is usually net. The authors carried out a series of experiments, and the influence of 3 kinds of treatments of pesticides, formalin 33 ppm+matachite green 0.15 ppm, dipterex 0.25 ppm, and furanace 0.1 ppm, to the filtering ability expressed as the consumption rate of dissolved oxygen and depletion of ammonia-nitrogen during the passing time through the filter layer was investigated, and it was found out that these pesticides with above mentioned concentrations which is normally used for controling several kinds of diseases and parasites during the time of eel culture, did not affect the filtering ability. Consequently, it can be said that these pesticides with above mentioned concentrations can he used without stopping filteration.

• The Journal of Information Systems
• /
• v.27 no.2
• /
• pp.1-28
• /
• 2018

Purpose More than 7.6 million mobile apps could be approved on both Apple iTunes Store and Google Play. For managing those existed Apps, Apple Inc. established twenty-four primary categories, as well as Google Play had thirty-three primary categories. However, all of their categorizations have appeared more and more problems in managing and classifying numerous apps, such as app miscategorized, cross-attribution problems, lack of categorization keywords index, etc. The purpose of this study focused on introducing individual information cognitive processing as the classification criteria to update the current categorization on Apple iTunes Store. Meanwhile, we tried to observe the effectiveness of the new criteria from a classification process on Apple iTunes Store. Design/Methodology/Approach A research approach with four research stages were performed and a series of mixed methods was developed to identify the feasibility of adopting individual information cognitive processing as categorization criteria. By using machine-learning techniques with Term Frequency-Inverse Document Frequency and Singular Value Decomposition, keyword lists were extracted. By using the prior research results related to car app's categorization, we developed individual information cognitive processing. Further keywords extracting process from the extracted keyword lists was performed. Findings By TF-IDF and SVD, keyword lists from more than five thousand apps were extracted. Furthermore, we developed individual information cognitive processing that included a categorization teaching process and learning process. Three top three keywords for each category were extracted. By comparing the extracted results with prior studies, the inter-rater reliability for two different methods shows significant reliable, which proved the individual information cognitive processing to be reliable as criteria of categorization on Apple iTunes Store. The updating suggestions for Apple iTunes Store were discussed in this paper and the results of this paper may be useful for app store hosts to improve the current categorizations on app stores as well as increasing the efficiency of app discovering and locating process for both app developers and users.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4A
• /
• pp.310-315
• /
• 2002

The Bark Coherence Function (BCF) defies a coherence function within perceptual domain as a new cognition module, robust to linear distortions due to the analog interface of digital mobile system. Our previous experiments have shown the superiority of BCF over current measures. In this paper, a new BCF suitable for VoIP is developed. The unproved BCF is based on the wavelet series expansion that provides good frequency resolution while keeping good time locality. The proposed Wavelet based Bark Coherence function (WBCF) is robust to variable delay often observed in packet-based telephony such as Voice over Internet Protocol (VoIP). We also show that the refinement of time synchronization after signal decomposition can improve the performance of the WBCF. The regression analysis was performed with VoIP speech data. The correlation coefficients and the standard error of estimates computed using the WBCF showed noticeable improvement over the Perceptual Speech Quality Measure (PSQM) that is recommended by ITU-T.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3060-3065
• /
• 2009

A series of wholly aromatic Poly(ether-ether-ester)s with flexible side chain was synthesized by direct polycondensation from ether linkaged triad diol and 2,5-dialkoxyterephthalic acid. The chemical structures and physical properties of these polymers were investigated by using $^1H$-NMR, FT-IR, DSC and TGA. As results of investigations, the inherent viscosities($\eta$inh) measured at $40^{\circ}C$ in 1,1,2,2-tetrachloroethane(TCE) were 0.45~0.86 dl/g and initial decomposition(Td) in TGA occurred at 378~418 $^{\circ}C$ in N2 gas. The majority of these polymers were soluble in organic solvents used in this experiments at elevated temperatures. Melting temperatures(Tm) decreased with increasing the length of the side chain and showed odd-even effects.

• Structural Engineering and Mechanics
• /
• v.59 no.3
• /
• pp.455-473
• /
• 2016

Methods for the seismic demands evaluation of structures require iterative procedures. Many studies dealt with the development of different inelastic spectra with the aim to simplify the evaluation of inelastic deformations and performance of structures. Recently, the concept of inelastic spectra has been adopted in the global scheme of the Performance-Based Seismic Design (PBSD) through Capacity-Spectrum Method (CSM). For instance, the Modal Pushover Analysis (MPA) has been proved to provide accurate results for inelastic buildings to a similar degree of accuracy than the Response Spectrum Analysis (RSA) in estimating peak response for elastic buildings. In this paper, a simplified nonlinear procedure for evaluation of the seismic demand of structures is proposed with its applicability to multi-degree-of-freedom (MDOF) systems. The basic concept is to write the equation of motion of (MDOF) system into series of normal modes based on an inelastic modal decomposition in terms of ductility factor. The accuracy of the proposed procedure is verified against the Nonlinear Time History Analysis (NL-THA) results and Uncoupled Modal Response History Analysis (UMRHA) of a 9-story steel building subjected to El-Centro 1940 (N/S) as a first application. The comparison shows that the new theoretical approach is capable to provide accurate peak response with those obtained when using the NL-THA analysis. After that, a simplified nonlinear spectral analysis is proposed and illustrated by examples in order to describe inelastic response spectra and to relate it to the capacity curve (Pushover curve) by a new parameter of control, called normalized yield strength coefficient (${\eta}$). In the second application, the proposed procedure is verified against the NL-THA analysis results of two buildings for 80 selected real ground motions.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.7
• /
• pp.2193-2199
• /
• 2012

A series of novel polytriazoleimides were prepared from various aromatic dianhydrides and a new kind of 1,2,3-triazole-containing aromatic diamine synthesized by the Cu (I)-catalyzed 1,3-dipolar cycloaddition reaction in DMAc, and characterized by FT-IR, $^1H$-NMR, XRD, DSC and TGA techniques. The results show the polytriazoleimides are soluble in most of strong polar solvents and have inherent viscosity values of 0.51-0.62 dL/g(DMAc). The polytriazoleimide films exhibit a tensile strength of 62.3-104.5 MPa and an elongation at breakage of 4.0-8.1%, a glass transition temperature ($T_g$) of $257-275^{\circ}C$, a decomposition temperature (at 5% weight loss) of $350-401^{\circ}C$ in $N_2$ atmosphere, and a dielectric constant of 2.47-3.01 at 10 MHz, which depend on the structure of the polymers. The polytriazoleimides perform good resistance to acid and alkali solution.