• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.1-10
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• 2021

The Internet of things (IoT) is the main advancement in data processing and communication technologies. In IoT, intelligent devices play an exciting role in wireless communication. Although, sensor nodes are low-cost devices for communication and data gathering. However, sensor nodes are more vulnerable to different security threats because these nodes have continuous access to the internet. Therefore, the multiparty security credential-based key generation mechanism provides effective security against several attacks. The key generation-based methods are implemented at sensor nodes, edge nodes, and also at server nodes for secure communication. The main challenging issue in a collaborative key generation scheme is the extensive multiplication. When the number of parties increased the multiplications are more complex. Thus, the computational cost of batch key and multiparty key-based schemes is high. This paper presents a Secure Multipart Key Distribution scheme (SMKD) that provides secure communication among the nodes by generating a multiparty secure key for communication. In this paper, we provide node authentication and session key generation mechanism among mobile nodes, head nodes, and trusted servers. We analyzed the achievements of the SMKD scheme against SPPDA, PPDAS, and PFDA schemes. Thus, the simulation environment is established by employing an NS 2. Simulation results prove that the performance of SMKD is better in terms of communication cost, computational cost, and energy consumption.

• 대한임베디드공학회논문지
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• 제17권6호
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• pp.375-382
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• 2022

This paper proposes a multi-core cooperative computing structure considering the heterogeneous features of automotive embedded on-chip software. The automotive embedded software has the heterogeneous execution flow properties for various hardware drives. Software developed with a homogeneous execution flow without considering these properties will incur inefficient overhead due to core latency and load. The proposed method was evaluated on an target board on which a automotive MCU (micro-controller unit) with built-in multi-cores was mounted. We demonstrate an overhead reduction when software including common embedded system tasks, such as ADC sampling, DSP operations, and communication interfaces, are implemented in a heterogeneous execution flow. When we used the proposed method, embedded software was able to take advantage of idle states that occur between heterogeneous tasks to make efficient use of the resources on the board. As a result of the experiments, the power consumption of the board decreased by 42.11% compared to the baseline. Furthermore, the time required to process the same amount of sampling data was reduced by 27.09%. Experimental results validate the efficiency of the proposed multi-core cooperative heterogeneous embedded software execution technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권3호
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• pp.794-815
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• 2023

The rapid development of mobile communication not only has made the industry gradually diversified, but also has enhanced the service quality requirements of users. In this regard, it is imperative to consider jointly network slicing and mobile edge computing. The former mainly ensures the requirements of varied vertical services preferably, and the latter solves the conflict between the user's own energy and harsh latency. At present, the integration of the two faces many challenges and need to carry out at different levels. The main target of the paper is to minimize the energy consumption of the system, and introduce a multi-slice joint task offloading and resource allocation scheme for massive multiple input multiple output enabled heterogeneous networks. The problem is formulated by collaborative optimizing offloading ratios, user association, transmission power and resource slicing, while being limited by the dissimilar latency and rate of multi-slice. To solve it, assign the optimal problem to two sub-problems of offloading decision and resource allocation, then solve them separately by exploiting the alternative optimization technique and Karush-Kuhn-Tucker conditions. Finally, a novel slices task offloading and resource allocation algorithm is proposed to get the offloading and resource allocation strategies. Numerous simulation results manifest that the proposed scheme has certain feasibility and effectiveness, and its performance is better than the other baseline scheme.

• 한국정보통신학회논문지
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• 제26권11호
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• pp.1577-1585
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• 2022

최근 4차산업혁명과 함께 메타버스에 대한 관심이 증가하는 가운데, 메타버스를 구축하는 멀티 에지 기반의 구조가 제시된다. 메타버스는 멀티 에지 시스템에서 많은 양의 영상처리와 데이터 전송을 통해 디지털 의사와 같은 시스템을 만들어 낼 수 있는 구조이다. 하지만 에지는 부족한 연산능력이라는 제약이 있으므로, 런타임 스트리밍이 가능한 서비스제공을 위해서는, 에지에서만 이루어졌던 영상처리와 데이터 전송을 에지-클라우드 협동을 통해 처리하여 저전력 시스템을 구축해야한다. 많은 에지들이 연결되는 시스템에서는, 그 무엇보다도 에지 경량화를 통해 효율적인 전체 시스템의 경량화 및 소모전력의 감소를 이루어낼 수 있다. 본 논문에서는 원격영상 처리방법과 Region of Interest (RoI) 기법을 사용하여, AI 소프트웨어의 저전력 런타임 스트리밍이 가능해지는, 에지-클라우드 협동 메타버스 애플리케이션을 제안한다. 에지-클라우드 협동 메타버스의 구조는 PC와 임베디드 보드를 사용하여 구현하였으며, 본 논문의 후반부에서는 에지의 시간 감소와 그에따른 전력 소모, 네트워크 통신량 감소를 검증하였다.

• Toxicological Research
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• 제6권2호
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• pp.167-182
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• 1990

Dietary restriction (caloric restriction) is the only intervention which has been reliably shown to extend the maximum life span of warm-blooded animals and delay the many phenomena associated with aging. It is also one of the most effective modulators of toxicity, especially cancer endpoints. In spite of the known modulator effects of caloric restriction, the biological mechanisms responsible for these effects had not been in vestigated until recently. The National Center for Toxicological Research (NCTR), in a collaborative effort with the National Institute of Aging (NIA), initiated a project whereby nine (9) combinations of rodent species/strains and diets were fed both restricted and ad libitum. The NIA's initiative was to identify biomarkers of aging whereas NCTR's initiative was to identify the biological effects associated with the profound effects caloric restriction has in protecting against both spontaneous (age-related) and chemically-induced toxic endpoints. Independent of sex or species, caloric restriction has similar effects on body temperature, oxygen consumption and $CO_2$production. Caloric restriction also decreased lipid glycolysis and metabolism in rats and mice, which suggest decreased production of metabolites which could lead to fatty acid epoxide formation. The age-associated loss of ciradian regulation of intermediate enzymes is also significantly reduced. Moreover, caloric restriction reduced the age-associated feminization of sexually dimorphic liver isozymes, increased several glucocorticoid responsive isozymes, elevated glucagon/insulin ratios, produced less microsomal superoxide and enhanced the capacity for utilzing detoxicating metabolic pathways. Calorically restricted rats have less than half the number of aflatoxin ($AFB_1$)-DNA adducts than ad libitum animals and urinary excretion of $AFB_1$ was increased significantly. Finally, DNA repair mechanisms are enhanced and oncogene expression is decreased in calorically restricted animals.

• STI Policy Review
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• 제7권2호
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• pp.60-84
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• 2016

What impact does the sharing economy have on existing businesses? This paper empirically examines how Uber transformed the taxi industry in New York City. Using a regression model controlling various potential influencing factors, we find no direct evidence that daily trips or revenue per taxi driver decreased since Uber entered the taxi industry. However, a closer investigation into other dimensions of taxi trips reveals that taxi drivers were forced to change their way of doing businesses to retain existing daily trips and revenue. Since Uber crowded out yellow taxis from the central area of Manhattan, yellow taxis responded by serving customers outside of the Manhattan borough. From enlarging their geographical coverage and serving customers that were previously ignored, yellow taxis were able to retain their previous level of taxi trips and market share. We also find that yellow taxis responded by improving their service quality to better serve customers' needs. Our result suggests that incumbents actively responded to Uber's entry and provided substantial benefit to consumers. Combined with the incumbent's response, the sharing economy transformed the existing market in a welfare-enhancing way. This paper provides managerial and policy implication on how incumbents affected by the disruptions of the sharing economy should respond. Even though it might be yet premature to examine the impact of Uber, results suggest that incumbents have effectively defended against Uber's entry so far. We conclude that the sharing economy and the existing economy can create positive value in our society through well-intentioned competition, complementing each other's weaknesses and strengths.

• 지식경영연구
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• 제22권3호
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• pp.55-73
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• 2021

공유 경제는 쓰지 않은 자원을 다른 사람들과 나누어 쓰는 협력적 소비로 인식되고 있다. 본 연구에서는 공유 숙박업 이용 고객들의 충성도에 영향을 미치는 요인들을 살펴보고자 하였다. 고객들이 공유 숙박업 경험에서 느낀 감정과 자아 이미지 일치성, 인지된 가치를 고객 충성도에 영향을 주는 선행요인으로 고려하였다. 그리고 진정한 경험, 숙소 시설, 가격 공정성을 공유 숙박업의 선택속성으로 고려하였다. Airbnb가 공유 숙박업에서 가장 큰 업체이기 때문에 설문 대상으로 선정하였다. 294명의 Airbnb 이용 고객 데이터를 바탕으로 구조 방정식 모형을 활용하여 요인들 간 관계를 분석하였다. 또한, Airbnb를 이용한 고객이 작성한 리뷰를 통해 고객이 어떤 사항을 중요하게 고려하였는지 살펴보았다. 이를 위해 네이버 블로그에서 Airbnb 리뷰를 수집하여 LDA기반 토픽모델링을 실시하였다. 본 연구 결과를 통해 공유 숙박업에 대한 고객들의 충성도에 영향을 미치는 요인들에 대한 이해를 바탕으로, 효과적인 마케팅 전략과 운영 관리 전략을 수립하는데 도움을 줄 수 있을 것으로 기대된다.

• 한국콘텐츠학회논문지
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• 제19권3호
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• pp.171-182
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• 2019

온라인 쇼핑몰의 대중화로 인해 소비자는 폭 넓은 소비의 기회를 제공받고 있다. 소비자들은 온라인 쇼핑몰에서 제공되는 실제 상품을 구매한 사용자의 리뷰, 상품의 자세한 정보와 같은 정보를 활용하여 상품의 구매 여부를 결정한다. 방대한 정보가 신뢰할 수 있는 정보인지는 소비자들이 스스로 판단해야만하기 때문에 객관적이며 신뢰할 수 있는 정보의 제공이 필요하다. 본 논문에서는 신뢰할 수 있는 상품의 추천을 위해서 상품의 신뢰도를 고려한 개인화된 추천 기법을 제안한다. 제안하는 추천 기법은 개인화 추천을 위해서 사용자의 다양한 행위를 기반으로 사용자의 선호도를 판별한다. 또한, 최신의 성향을 반영하기 위해서 시간 가중치를 고려한 사용자 선호도 계산 방법을 제안한다. 마지막으로 사용자가 사용하지 않았던 상품에 대한 선호 점수를 예측하고 예측 점수가 높은 상품 중 신뢰도가 높은 상품들을 추천한다.

• 융합정보논문지
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• 제9권8호
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• pp.110-122
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• 2019

글로벌 경제 위기와 함께 시작된 공유경제 기업의 성공은 공유경제를 스타트업으로 여겨왔던 기존의 인식을 전환하게 만든 계기가 되어 최근에는 전통적인 대기업들도 제휴나 인수합병을 통해 공유경제 사업에 뛰어들고 있다. 그러나 공유경제의 확산과 함께 사회적 논쟁도 뜨겁게 진행되고 있다. 공유서비스 거래 프로세스 신뢰의 문제, 시민의식의 부족 등은 안정된 공유경제 서비스 공급과 확대에 장애가 되고 있으며, 기존 산업을 위협하여 실물경제를 위축시키고 불법과 탈세 등 법질서의 혼란을 초래할 우려가 크다. 이에 본 연구에서는 공유서비스 사용에 대한 동기요인을 촉진요인과 저해요인으로 구분하여 규명하고 이에 대한 사용자들의 인식을 실증분석 하였다. 연구 결과는 공유서비스 사용자들의 위험 인식을 줄이고 공유 시스템 참여를 활성화하는 지침으로 사용될 수 있을 것이다. 또한 공유경제 서비스 유형을 세 가지로 분류하고 각 유형별 동기요인에 대한 집단 간 인식의 차이를 검증하였으며, 이러한 분석 결과는 공유서비스 유형별로 비즈니스 촉진을 위한 최적의 전략 수립을 모색하는 데 적용할 수 있을 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권11호
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• pp.3565-3583
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• 2022

The task scheduling problem has received a lot of attention in recent years as a crucial area for research in the cloud environment. However, due to the difference in objectives considered by service providers and users, it has become a major challenge to resolve the conflicting interests of service providers and users while both can still take into account their respective objectives. Therefore, the task scheduling problem as a bi-objective game problem is formulated first, and then a task scheduling model based on the bi-objective game (TSBOG) is constructed. In this model, energy consumption and resource utilization, which are of concern to the service provider, and cost and task completion rate, which are of concern to the user, are calculated simultaneously. Furthermore, a many-objective evolutionary algorithm based on a partitioned collaborative selection strategy (MaOEA-PCS) has been developed to solve the TSBOG. The MaOEA-PCS can find a balance between population convergence and diversity by partitioning the objective space and selecting the best converging individuals from each region into the next generation. To balance the players' multiple objectives, a crossover and mutation operator based on dynamic games is proposed and applied to MaPEA-PCS as a player's strategy update mechanism. Finally, through a series of experiments, not only the effectiveness of the model compared to a normal many-objective model is demonstrated, but also the performance of MaOEA-PCS and the validity of DGame.