• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권5호
• /
• pp.1984-2002
• /
• 2020

With the appearance of wireless spectrum crisis in traditional cellular network, device-to-device (D2D) communication has been regarded as a promising solution to ease heavy traffic burden by enabling precise content delivery among mobile users. However, due to the channel sharing, the interference between D2D and cellular users can affect the transmission rate and narrow the throughput in the network. In this paper, we firstly present a weighted interference minimization cluster formation model involving both social attribute and physical closeness. The weighted-interference, which is evaluated under the susceptible-infected(SI) model, is utilized to gather user in social and physical proximity. Then, we address the cluster formation problem via spectrum clustering with iterative operation. Finally, we propose the stable matching theory algorithm in order to maximize rate oriented to accomplish the one-to-one resource allocation. Numerical results show that our proposed scheme acquires quite well clustering effect and increases the accumulative transmission rate compared with the other two advanced schemes.

• 천문학회보
• /
• 제42권1호
• /
• pp.54.3-55
• /
• 2017

The nature and physical environments of SNRs are diverse, and for this reason, the understanding of the properties of nearby SNRs is useful in interpreting the emission from SNRs in remote galaxies where we cannot resolve them. In this regard, the LMC is a unique place to study SNRs due to its proximity, location, and composition compared with our galaxy. We carried out a multi-wavelength study of SNR N63A in the LMC, a young remnant of the SN explosion of one of the most massive (> 40 Msun) stars in a cluster. It is currently expanding within a large H II region formed by OB stars in the cluster and engulfing a molecular cloud (MC). As such, N63A is a prototypical SNR showing the impact of SN explosion on the cluster and its environment. Its morphology varies strongly across the wave bands, e.g. the size in X-ray is three times larger than in optical. However, the bright optical nebula would correspond to a MC swept up by the SNR, and consequently the interaction SNR-MC is limited to the central portion of the SNR. We aimed to study the overall structure of N63A, using near-IR imaging and spectroscopic observations to obtain the physical parameters of the atomic shocks, and also to understand how the SNR- MC interaction works and reveal the structure of the shocked cloud as well as the consequences of the impact of the SNR shock on the MC, comparing information obtained in different wavelengths.

• Journal of Contemporary Eastern Asia
• /
• 제18권1호
• /
• pp.189-216
• /
• 2019

The frequent occurrence of overwhelming disasters necessitates risk communication systems capable of operating effectively in disaster contexts. Few studies have examined risk communication networks during disasters through social networking services (SNS). This study therefore investigates the patterns of risk communication by comparing Korean and international networks based on the social amplification of risk communication in the context of the Sewol ferry disaster (SFD). In addition, differences in language use and patterns between Korean and international contexts are identified through a semantic analysis using KrKwick, NodeXL, and UCINET. The SFD refers to the sinking of the ferry while carrying 476 people, mostly secondary school students. The results for interpersonal risk communication reveal that the structure of the Korean risk communication network differed from that of the international network. The Korean network was more fragmented, and its clustering was more sparsely knitted based on the impact and physical proximity of the disaster. Semantic networks imply that the physical distance from the disaster affected the content of risk communication, as well as the network pattern.

• Journal of the Korean Physical Society
• /
• 제73권10호
• /
• pp.1589-1595
• /
• 2018

Similarity index measures the topological proximity of node pairs in a complex network. Numerous similarity indices have been defined and investigated, but the dependency of structure on the performance of similarity indices has not been sufficiently investigated. In this study, we investigated the relationship between the performance of similarity indices and structural properties of a network by employing a two-state random network. A node in a two-state network has binary types that are initially given, and a connection probability is determined from the state of the node pair. The performances of similarity indices are affected by the number of links and the ratio of intra-connections to inter-connections. Similarity indices have different characteristics depending on their type. Local indices perform well in small-size networks and do not depend on whether the structure is intra-dominant or inter-dominant. In contrast, global indices perform better in large-size networks, and some such indices do not perform well in an inter-dominant structure. We also found that link prediction performance and the performance of similarity are correlated in both model networks and empirical networks. This relationship implies that link prediction performance can be used as an approximation for the performance of the similarity index when information about node type is unavailable. This relationship may help to find the appropriate index for given networks.

• 천문학회보
• /
• 제45권1호
• /
• pp.62.1-62.1
• /
• 2020

We present a scaling relation between black hole (BH) mass and bulge luminosity for 35 nearby (z<0.1) type 1 active galaxies, selected from the 70-month Swift-BAT X-ray source catalog. Thanks to the unbiased selection and proximity of the parent sample, our sample is suitable to study the physical connection between central black holes and host galaxies. We use the F814W images obtained with the Advanced Camera for Surveys on Hubble Space Telescope, to perform the imaging decomposition with GALFIT. With a careful treatment on the PSF model, we measure the I-band bulge brightness robustly. In combination with the BH mass estimated from a single-epoch spectroscopic data, we present the correlation between BH mass and bulge luminosity of the target AGNs. We demonstrate that our sample marginally lies off from the M(BH)-L(bulge) relation of inactive galaxies. We discuss possible physical origins of this discrepancy. Finally, we present how the relation depends on the photometric properties of AGNs and host galaxies, which may provide an useful insight on the co-evolution between BHs and host galaxies.

• 한국산학기술학회논문지
• /
• 제16권2호
• /
• pp.1006-1015
• /
• 2015

본 연구에서는 공급사슬 네트워크에서 네트워크 기반 기업 간 기술의 적용과 그 확산에 영향을 주는 요인을 도출하고 요인들 간의 관계를 밝히고자 한다. 공급사슬관리의 효율성과 전체 최적화의 달성을 위해 도입된 기업 간 기술은 공급사슬 내 기업들의 적극적인 기술 도입과 공급사슬 네트워크상 빠른 확산이 필요하다. 하지만, 각 기업들마다 내 외부적인 요인들에 의해 도입시점이 각기 다르며 이로 인해 그 기술의 확산속도가 결정되어 진다. 특히, 공급사슬 상에 다수의 공급업체들이 존재하는 경우, 새로운 기술의 도입을 고려중인 잠재적 대상은 기업 내부적 요인뿐만 아니라 다른 기업들과의 관계요인에 의해 결정되어지는데, 관계 요인에 의한 영향은 그 기업과의 물리적 또는 사회적 접근성에 의해 결정된다. 본 연구는 미국 유통산업 내 소비재제품제조업체(CPG)들에게 도입된 기업 간 네트워크 기술 중의 하나인 재고추적기술의 도입과 확산에 대한 실증적 분석을 통해, 잠재적 사용자의 기술 도입 결정이 초기에는 몇몇 기업들의 내부적 요인의 영향에 의해 확산이 되다가 점차적으로 사회적 접근성과 같은 관계요인에 의해 영향을 받으며 공급사슬 전체적으로 기술 확산이 일어나는 것을 확인하였다.

• Restorative Dentistry and Endodontics
• /
• 제41권4호
• /
• pp.296-303
• /
• 2016

Objectives: The purpose of the present study was to evaluate the effects of proanthocyanidin (PAC), a crosslinking agent, on the physical properties of a collagen hydrogel and the behavior of human periodontal ligament cells (hPDLCs) cultured in the scaffold. Materials and Methods: Viability of hPDLCs treated with PAC was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The physical properties of PAC treated collagen hydrogel scaffold were evaluated by the measurement of setting time, surface roughness, and differential scanning calorimetry (DSC). The behavior of the hPDLCs in the collagen scaffold was evaluated by cell morphology observation and cell numbers counting. Results: The setting time of the collagen scaffold was shortened in the presence of PAC (p < 0.05). The surface roughness of the PAC-treated collagen was higher compared to the untreated control group (p < 0.05). The thermogram of the crosslinked collagen exhibited a higher endothermic peak compared to the uncrosslinked one. Cells in the PAC-treated collagen were observed to attach in closer proximity to one another with more cytoplasmic extensions compared to cells in the untreated control group. The number of cells cultured in the PAC-treated collagen scaffolds was significantly increased compared to the untreated control (p < 0.05). Conclusions: Our results showed that PAC enhanced the physical properties of the collagen scaffold. Furthermore, the proliferation of hPDLCs cultured in the collagen scaffold crosslinked with PAC was facilitated. Conclusively, the application of PAC to the collagen scaffold may be beneficial for engineering-based periodontal ligament regeneration in delayed replantation.

• 한국생물정보학회:학술대회논문집
• /
• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
• /
• pp.221-227
• /
• 2005

THEMATICS is a simple computational method for predicting functional sites in proteins. The method computes the theoretical titration curves of the ionizable residues of a protein using its 3D structure, determines the residues with perturbed, non-Henderson-Hasselbalch titration behavior, and identifies clusters of these perturbed residues in physical proximity. We have shown previously that this method is highly successful in predicting catalytic sites in enzymes. In the present study, we apply the method to non-catalytic ligand-binding proteins. It is shown that THEMATICS can predict non-catalytic binding sites. The success rate is better than 80 % for a set of 30 non-catalytic, ligand-binding proteins. The application of the method to Glutamine-binding protein from E. coli is discussed in detail.

• 한국주거학회:학술대회논문집
• /
• 한국주거학회 1996년도 학술발표대회논문집
• /
• pp.21-28
• /
• 1996

The Purpose of this study was to identify the effects of the elderly Koreans of residential relocation and to find their conditioning variables that mediate some of the negative effects of residential relocation. The research was performed by questionnares. Subject samples consisted of 448 elderly individuals who have lived for two years or less in one of the two new residential communities in commuting proximity with Seoul: Ilsan or Bundang. Two variables measured for the life of the elderly to residential relocation were the change of the social relationship network and the change of the depression level. Results indicated that the relocation had a substantial disrupting effect on the social network of the elderly. The level of depression of the subjects after relocation was decresed. It was also found that the effects of the elderly to residential relocation was mainly affected by physical factors of environment and residential satisfaction.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2002년도 춘계학술발표논문집
• /
• pp.106-108
• /
• 2002

반도체 physical layout design rule이 작아짐에 따라 Proximity effect와 overlay가 Pattern 구현에 크게 영향을 미치고 있다. Metal layer와 contact의 부족한 overlay margin으로 overlay 불량이 발생하고, 감소한 space margin으로 인해 bridge와 같은 문제가 나타난다. 따라서, resolution을 향상시키고, 최소한의 overlay margin을 확보함으로써 미세 pattern의 구현을 가능하게 한다. 이를 위해 OPC와 attPSM 같은 분해능향상기술이 사용된다. 그러나 attPSM의 사용은 원하지 않는 pattern이 생성되는 sidelobe와 같은 문제가 발생한다. 따라서 serial image simulation올 통해 추출한 rule을 rule-based correction에 적용하여 sidelobe현상을 방지한다. 그리고 overlay margin 부족으로 나타나는 문제는 metal layer와 contact overlap되는 영역의 line edge를 확장하고, rule checking을 통해 최소한의 space margin을 확보하여 해결한다 따라서 overlay error를 rule-based correction을 사용하여 효과적으로 방지한다.