• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.9
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• pp.3907-3923
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• 2020

An enhanced irregular repetition slotted ALOHA (IRSA) protocol is proposed by using polarization characteristic of satellite link and MIMO detection in low earth orbit (LEO) satellite networks, which is dubbed polarized MIMO IRSA (PM-IRSA). In the proposed scheme, one or two packets in one slot can be decoded by employing polarized MIMO detection, and more than two collided packets in multiple slots which can construct the virtual MIMO model can be decoded by the MIMO detection algorithm. The performance of the proposed scheme is analyzed with the density evolution (DE) approach and the degree distribution is optimized to maximize the system throughput by using a differential evolution. Numerical results certify our analysis and show that the normalized throughput of the proposed PM-IRSA can achieve 1.89 bits/symbol.

• Carbon letters
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• v.26
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• pp.61-65
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• 2018

Comprehensive calculations of the Rh decoration effect on zigzag CNTs with n ranging from 7 to 12 were conducted in this work to understand the effect of Rh doping on geometric structures and electronic behaviors upon metallic and semiconducting CNTs. The obtained results indicated that Rh dopant not only contributes to the deformation of C-C bonds on the sidewall of CNTs, but also transforms the electron distribution of related complexes, thereby leading to a remarkable increase of the conductivity of pure CNTs given the emerged novel state within the energy gap for metallic CNTs and the narrowed energy gap for semiconducting CNTs. Our calculations will be meaningful for exploiting novel CNT-based materials with better sensitivity to electrons and higher electrical conductivity compared with pure CNTs.

• The Journal of Society for e-Business Studies
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• v.9 no.1
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• pp.209-220
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• 2004

If protocol has fast operations and short key length, it can be efficient user authentication protocol. Lenstra and Verheul proposed XTR. XTR have short key length and fast computing speed. Therefore, this can be used usefully in complex arithmetic. In this paper, to design efficient user authentication protocol we used a subgroup of Galois Field to problem domain. Proposed protocol does not use GF(p/sup 6/) that is existent finite field, and uses GF(p²) that is subgroup and solves problem. XTR-ElGamal based user authentication protocol reduced bit number that is required when exchange key by doing with upside. Also, proposed protocol provided easy calculation and execution by reducing required overhead when calculate. In this paper, we designed authentication protocol with y/sub i/ = g/sup b.p/sup 2(i-1)//ㆍv mol q, 1(equation omitted) 3 that is required to do user authentication.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.123-127
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• 2001

This paper proposed for allotment of group key's rekey interval required from secure multicast environment. New group key distribution occurs in two cases: one is periodical update and the other is permitted or unpermitted withdrawal of group member. In later case, the group controller distributes new group key to member except withdrawal member because it can't predict precisely. In former case, the group member who cheated the group can adjust the rekey interval. Using relation between security level, overhead and cost from rekey interval, this paper suggests effective rekey interval allotment through probable performance analysis in large dynamic group.

• ETRI Journal
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• v.37 no.3
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• pp.512-522
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• 2015

Recent developments in identity-based cryptography (IBC) have provided new solutions to problems related to the security of mobile ad hoc networks (MANETs). Although many proposals to solve problems related to the security of MANETs are suggested by the research community, there is no one solution that fits all. The interdependency cycle between secure routing and security services makes the use of IBC in MANETs very challenging. In this paper, two novel methods are proposed to eliminate the need for this cycle. One of these methods utilizes a key pool to secure routes for the distribution of cryptographic materials, while the other adopts a pairing-based key agreement method. Furthermore, our proposed methods utilize threshold cryptography for shared secret and private key generation to eliminate the "single point of failure" and distribute cryptographic services among network nodes. These characteristics guarantee high levels of availability and scalability for the proposed methods. To illustrate the effectiveness and capabilities of the proposed methods, they are simulated and compared against the performance of existing methods.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.717-726
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• 2021

Tourism is one of the key economic drivers not only in Vietnam but also in the world. This study explores the awareness and perceptions of key stakeholders such as local residents, tourism businesses, and tourists on sustainable tourism development in the Mekong Delta in Vietnam. Both quantitative and qualitative research approaches have been used with the secondary and primary data to provide insights on the subject. The secondary data is from vast sources, including the governmental department of tourism, statistical departments, annual all-level governmental reports, businesses, and others. The primary data is from the survey by questionnaires with 230 enterprises, 720 local residents, and 670 tourists and from the semi-structured and in-depth interviews conducted with local residents, businesses, tourists, local authorities' officers, and especially with 5 experts who are also stakeholders of Mekong Delta tourism. The results will help the related authorities understand the awareness and perceptions of the key stakeholders and deliver valuable information and a concrete delineated roadmap toward sustainable tourism development of the research settings.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.74-96
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• 2023

At present, the smart grid has become one of the indispensable infrastructures in people's lives. As a commonly used communication method, wireless communication is gradually, being widely used in smart grid systems due to its convenient deployment and wide range of serious challenges to security. For the insecurity of the schemes based on large integer factorization and discrete logarithm problem in the quantum environment, an identity-based key management scheme for smart grid over lattice is proposed. To assure the communication security, through constructing intra-cluster and inter-cluster multi-hop routing secure mechanism. The time parameter and identity information are introduced in the relying phase. Through using the symmetric cryptography algorithm to encrypt improve communication efficiency. Through output the authentication information with probability, the protocol makes the private key of the certification body no relation with the distribution of authentication information. Theoretic studies and figures show that the efficiency of keys can be authenticated, so the number of attacks, including masquerade, reply and message manipulation attacks can be resisted. The new scheme can not only increase the security, but also decrease the communication energy consumption.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.293-294
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• 2007

• Journal of Distribution Science
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• v.10 no.10
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• pp.5-9
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• 2012

Purpose - The purpose of this study is to explore, examine, and analyze Journal of Distribution Science and its articles based on five key factors of journal selection process by Thompson and to provide foundations for further knowledge creation and theory building in the areas of distribution and distribution science. Research design, data, methodology - This study used an exploratory case study method to engage article analysis and reviews of Journal of Distribution Science. Thompson's five journal selection factors were used as criteria for the journal and article analyses and review. Results - Journal of Distribution Science is currently meeting or at least in the progress of meeting the following factors: timeliness of publication, international editorial convention, international diversity, and citation analysis. However, JDS is short of meeting the factor of editorial content. The research topics were not new, emerging, and/or distinctive, and they were not directly associated with specific region or country other than Korea. Conclusions - The findings from this study could lead the field of distribution to reexamine the core knowledge, to reestablish the fundamental concepts and principles, to formulate and propose academically and practically sound research methods, and to develop and focus on unique research topics in the area of distribution.

• Journal of Distribution Science
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• v.21 no.6
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• pp.69-81
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• 2023

Purpose: The study investigates the moderating impact of interpersonal mindfulness (IM) on the link between perceived similarity (OPS), physical appearance (OPA), and suitable behavior (OSB) - three key factors of other consumer perception (OCP) and brand experience (BE) in distribution of OCP and brand. Research design, data, and methodology: This study collected data from 612 consumers at shopping malls. SmartPLS 3.3.9 software were used to assess the measurement model and structural model. Results: According to the study's findings, IM has a negative modality in the impact between BE and OPS, OPA, and OSB. That also demonstrates how distribution of OCP and brand can affect a person's brand experience. Conclusions: The distribution of OCP and IM interactions have a significant influence on the brand experience in brand distribution. The study's results show that IM including mindfulness will function as a moderator between perceived similarity, physical appearance, suitable behavior regarded proper by other consumers, and brand experiences; therefore, they impact to brand distribution. The findings give a foundation for further IM research and add to the brand distribution theory that already exists. The findings also have some managerial implications in brand distribution.