• Journal of the Chungcheong Mathematical Society
• /
• v.18 no.2
• /
• pp.161-173
• /
• 2005

In this paper, we will introduce the folding on the connected sum of some types of manifolds which are determined by their fundamental group. Also, the fundamental group of the unfolding of the connected sum will be deduced some types of conditional foldings restricted on the elements of the fundamental groups are deduced. Theorems governing these relations will be achieved. Some applications in manufacturing are presented.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.10
• /
• pp.2653-2659
• /
• 1996

In this paper, DC-free and minimum bandwidth binary line codes with look-up table are proposed and their performances are analyzed. As results of performance analysis, the proposed codes are shown to have spectral nulls at DC and Nyquist frequency. Among the proposed codes, binary line codes of which both codeword digital sum and alternating digital sum are zero have lower code rate but better spectral characteristics. Furthermore, binary line codes which consist of all codewords including those with nonzero digital sum and alternating digital sum have worese spectral characteristics but higher code rate.

• Communications of the Korean Mathematical Society
• /
• v.36 no.2
• /
• pp.389-400
• /
• 2021

For a graph G, the variable sum exdeg index SEI_a(G) is defined as Σ_u∈V(G)d_G(u)a^d_G(u), where a ∈ (0, 1) ∪ (1, +∞). In this work, we determine the minimum and maximum variable sum exdeg indices (for a > 1) of n-vertex cactus graphs with k cycles or p pendant vertices. Furthermore, the corresponding extremal cactus graphs are characterized.

• The korean journal of orthodontics
• /
• v.18 no.2
• /
• pp.407-420
• /
• 1988

The primary objective of this study was to make the prediction percentile tabulation of the sum of mesiodistal widths of the unerupted permanent canines and premolars derived from the sum of mesiodistal widths of the erupted permanent incisors in normal and crowding groups. Crowding group consisted of 85 pairs of dental casts (42 males and 43 females) with more than 4mm of crowding in anteriors. Normal group consisted of 109 pairs of dental casts (65 males and 44 females) with less than 1mm of spacing or crowding in anteriors. The mesiodistal crown diameters of permanent teeth were measured from the dental casts using the sliding calipers (Mitutoyo Co., Japan). From the study, the obtained results were as follows: There were not significant differences between male and female in both groups on the basis of the ratios between the sum of mesiodistal widths of incisors and the sum of mesiodistal widths of canines and premolars. There was not significant difference between two groups on the basis of the ratio between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of mandibular canines and premolars and was significant differences between two groups on the basis of the ratio between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of maxillary canines and premolars. There was significant difference between two groups on the basis of the ratio between the sum of mesiodistal widths of maxillary incisors and the sum of mesiodistal widths of mandibular canines and premolars. There was significant difference between two groups on the basis of the ratio between the sum of mesiodistal widths of maxillary incisors and the sum of mesiodistal widths of maxillary canines and premolars. The percentile prediction tabulations were made in an attempt to predict the sum of mesiodistal widths of the unerupted permanent canines and premolars derived from the sum of mesiodistal widths of the erupted permanent mandibular incisors in each group. The percentile prediction tabulations were made in an attempt to predict the sum of mesiodistal widths of the unerupted permanent canines and premolars derived from the sum of mesiodistal widths of the erupted permanent maxillary incisors in each group.

• Journal of the Korea Computer Graphics Society
• /
• v.16 no.2
• /
• pp.9-17
• /
• 2010

Minkowski sum of two polyedra is an operation to compute the sum of all pairs of points contained in the polyhedra. It has been a very useful tool to solve many geometric problems arising in the areas of robotics, NC machining, solid modeling, and so on. However, very few algorithms have been proposed to compute Minkowski sum of polyhedra, because computing Minkowski sum boundaries is susceptible to roundoff errors. We propose an algorithm to robustly compute the Minkowski sum boundaries by employing the controlled linear perturbation scheme to prevent numerically ambiguous and degenerate cases from occurring. According to our experiments, our algorithm computes the Minkowski sum boundaries with the precision of $10^{-14}$ by perturbing the vertices of the input polyhedra up to $10^{-10}$.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.85-88
• /
• 2003

Polycyclic aromatic hydrocarbons (PARs) are an important group of organic contaminants present in sewage sludge, due to their persistence, toxic, bioaccumulative and long range transfer. These characters make themselves as Persistent Organic Pollutants(POPs) in Long Range Transboundary Air Pollutions convention(LRT AP) of Europe. A method of the gas chromatographic-mass spectrometric (GC-MS) determination of PARs present in sewage sludge was developed and applied to analyzed samples from five sewerage treatment plants (SWTPs), having different treatment types. PARs were extracted from freeze-dried samples by toluene 16 hours in a soxhlet extraction system. The sludge extracts were cleaned-up by an activated silica gel column chromatography. The sum of the 16 US Environmental Protection Agency PARs sewage sludge samples varied from 2.44 to 4.82 ${\mu}g$/g. Concentration of emission carcinogen PARs(PARcarc), such as Benzo(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenzo(a, h)anthracene and Indeno(1, 2, 3-cd)pyrene ranged from 0.62 to 1.03 ${\mu}g$/g. The total amount of PAHs emission from sewage sludge in Korea was calculated as a top-down approach. PARs and $\sum$PAHcarc from sewage treatment plants had several pathway each by-products. In the ocean dumping, PAHs and $\sum$PAHcarc emissions were 1155.95 kg/year and 5040.32 kg/year. In recycle, PAHs and $\sum$PAHcarc emissions were 98.36 kg/year and 428.87 kg/year. In the landfill, PAHs and $\sum$PAHcarc emissions were 190.40 kg/year and 830.21 kg/year. In the incineration, PAHs and $\sum$PAHcarc emission were 33.10 kg/year and 830.21 kg/year. (In case of incineration, the whole provisions of PARs and $\sum$PAHcarc contained to flowed in sludge was supposed to be exhausted to environment through exhaust after incineration.)

• Journal of Broadcast Engineering
• /
• v.25 no.1
• /
• pp.36-47
• /
• 2020

The improved belief-propagation-based algorithms, such as normalized min-sum algorithm (NMSA) or offset min-sum algorithm (OMSA), are widely used to decode LDPC(Low-Density Parity-Check) codes because they are less computationally complex and work well even at low SNR(Signal-to-Noise Ratio). However, these algorithms work well only when an appropriate normalization factor or offset value is used. A new method that uses a CMD(Check Node Message Distribution) chart and least-square method, which has been recently proposed, has advantages on computational complexity over other approaches to get optimal coefficients. Furthermore, this method can be used to derive coefficients for each iteration. In this paper, we apply this method and propose an algorithm to derive a combination of normalization factor and offset value for a combined normalized and offset min-sum algorithm to further improve the decoding of LDPC codes. Simulations on the next-generation broadcasting standards, ATSC 3.0 LDPC codes, prove that a combined normalized and offset min-sum algorithm which takes the proposed coefficients as correction coefficients shows the best BER performance among other decoding algorithms.

• Water for future
• /
• v.10 no.1
• /
• pp.79-94
• /
• 1977

This study is aimed at the establishment and examination of stochastic model to simulate Run-length and Run-sum of daily rainfall and streamflow. In the analysis, daily rainfall records in major cities (Seoul, Kangnung, Taegu, Kwangju, Busan, and Cheju) and daily streamflow records of Major rivers (Han, Nakdong and Geum River) were used. Also, the fitness of daily rainfall and streamflow to Weibull and one parameter exponential distribution was tested by Chi-square and Kolmogorov-Smirnov test, from which it was found that daily rainfall and streamflow generally fit well to exponential type distribution function. The Run-length and Run-sum were simulated by the Weibull Model (WBL Model), one parameter exponential model (EXP-1 Model) based on the Nonte Carlo technique. In this result, Run-length of rainfall was fitted for one parameter exponential model and Run-length of streamflow was fitted for Weibull model. And Run-sum of rainfall and streamflow were fit comparatively for regression model. Hereby, statistical charactristics of Simulation data were sinilar to historical data.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.7
• /
• pp.560-570
• /
• 2013

In this paper, we propose transceiver design strategies for the two-cell multiple-input multiple-output (MIMO) interfering broadcast channel where inter-cell interference (ICI) exists in addition to inter-user interference (IUI). We first formulate the generalized zero-forcing interference alignment (ZF-IA) method based on the alignment of IUI and ICI in multi-dimensional subspace. We then devise a minimum weighted-mean-square-error (WMSE) method based on "regularizing" the precoders and decoders of the generalized ZF-IA scheme. In contrast to the existing weighted-sum-rate-maximizing transceiver, our method does not require an iterative calculation of the optimal weights. Because of this, the proposed scheme, while not designed specially to maximize the sum-rate, is computationally efficient and achieves a faster convergence compared to the known weighed-sum-rate maximizing scheme. Through analysis and simulation, we show the effectiveness of the proposed regularized ZF-IA scheme.

• Communications for Statistical Applications and Methods
• /
• v.30 no.6
• /
• pp.631-652
• /
• 2023

In the two-condition within-subject mediation design, pairs of variables such as mediator and outcome are observed under two treatment conditions. The main objective of the design is to investigate the indirect effects of the condition difference (sum) on the outcome difference (sum) through the mediator difference (sum) for comparison of two treatment conditions. The natural condition variables mean the original variables, while the rotated condition variables mean the difference and the sum of two natural variables. The outcome difference (sum) is expressed as a linear model regressed on two natural (rotated) mediators as a parallel two-mediator design in two condition approaches: the natural condition approach uses regressors as the natural condition variables, while the rotated condition approach uses regressors as the rotated condition variables. In each condition approach, the total indirect effect on the outcome difference (sum) can be expressed as the sum of two individual indirect effects: within- and cross-condition indirect effects. The total indirect effects on the outcome difference (sum) for both condition approaches are the same. The invariance of the total indirect effect makes it possible to analyze the nature of two pairs of individual indirect effects induced from the natural conditions and the rotated conditions. The two-condition within-subject design is extended to the addition of a between-subject moderator. Probing of the conditional indirect effects given the moderator values is implemented by plotting the bootstrap confidence intervals of indirect effects against the moderator values. The expected indirect effect with respect to the moderator is derived to provide the overall effect of moderator on the indirect effect. The model coefficients are estimated by the structural equation modeling approach and their statistical significance is tested using the bias-corrected bootstrap confidence intervals. All procedures are evaluated using function lavaan() of package {lavaan} in R.