• Interdisciplinary Bio Central
• /
• 제3권2호
• /
• pp.8.1-8.6
• /
• 2011

Background: Thanks to the development of the mathematical/statistical reverse engineering and the high-throughput measuring biotechnology, lots of biologically meaningful genegene interaction networks have been revealed. Steady-state analysis of these systems provides an important clue to understand and to predict the systematic behaviours of the biological system. However, modeling such a complex and large-scale system is one of the challenging difficulties in systems biology. Results: We introduce a new stochastic modeling approach that can describe gene regulatory mechanisms by dividing two (DNA and protein) layers. Simple queuing system is employed to explain the DNA layer and the protein layer is modeled using G-networks which enable us to account for the post-translational protein interactions. Our method is applied to a transcription repression system and an active protein degradation system. The steady-state results suggest that the active protein degradation system is more sensitive but the transcription repression system might be more reliable than the transcription repression system. Conclusions: Our two layer stochastic model successfully describes the long-run behaviour of gene regulatory networks which consist of various mRNA/protein processes. The analytic solution of the G-networks enables us to extend our model to a large-scale system. A more reliable modeling approach could be achieved by cooperating with a real experimental study in synthetic biology.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권7호
• /
• pp.2668-2717
• /
• 2021

Demands for high-speed wireless data services grow rapidly. It is a big challenge to increasing the network capacity operating on licensed spectrum resources. Unlicensed spectrum cellular networks have been proposed as a solution in response to severe spectrum shortage. Licensed Assisted Access (LAA) was standardized by 3GPP, aiming to deliver data services through unlicensed 5 GHz spectrum. Furthermore, the 3GPP proposed 5G New Radio-Unlicensed (NR-U) study item. On the other hand, artificial intelligence (AI) has attracted enormous attention to implement 5G and beyond systems, which is known as Intelligent Radio (IR). To tackle the challenges of unlicensed spectrum networks in 4G/5G/B5G systems, a lot of works have been done, focusing on using Machine Learning (ML) to support resource allocation in LTE-LAA/NR-U and Wi-Fi coexistence environments. Generally speaking, ML techniques are used in IR based on statistical models established for solving specific optimization problems. In this paper, we aim to conduct a comprehensive survey on the recent research efforts related to unlicensed cellular networks and IR technologies, which work jointly to implement 5G and beyond wireless networks. Furthermore, we introduce a positioning assisted LTE-LAA system based on the difference in received signal strength (DRSS) to allocate resources among UEs. We will also discuss some open issues and challenges for future research on the IR applications in unlicensed cellular networks.

• 한국시뮬레이션학회논문지
• /
• 제14권2호
• /
• pp.83-92
• /
• 2005

Access networks connected in B3G networks provide its property network service. Hence, though mobile users may utilize only a network service from an access network, they can also use variety of network services from several access networks for their service satisfaction. To support heterogeneous changeable network service in access networks, the mobile terminal must implement heterogeneous system techniques so that it is able to change the network service by ISHO (Inter-System Handover) In this paper, we present the ISHO condition by the policy-based framework in B3G networks. Also, we propose an ISHO scheme to control network resources for the QoS management of a mobile session between UMTS and WLAN access networks. To support the QoS management, the proposed scheme is that it will be implemented before the resource exhaustion occurs to effect network performances.

• 한국컴퓨터정보학회논문지
• /
• 제16권3호
• /
• pp.157-165
• /
• 2011

B3G 네트워크에서 SLA 기반 QoS 관리방안은 서비스 이용자와 서비스 제공자 사이에서 이루어지는 협약으로 서비스 제공자는 협약된 사항을 근거로 사용자에게 통신 서비스를 제공하게 된다. 서비스 제공자는 협의된 서비스 레벨을 유지하기 위한 QoS 방안을 제공하며 이는 정책레벨에서 시스템 레벨까지의 세부방안을 포괄하여 다룬다. 협약된 서비스 정책에 의하여 서비스 제공자는 서비스 사용자와의 협약에 맞추어 정해진 QoS를 제공하며, 따라서 서비스 사용자는 신뢰적으로 서비스를 제공받을 수 있다. 따라서 본 논문에서는 B3G 네트워크에서 SLA 기반에서 이루어질 수 있는 서비스 협약을 통하여 사용자 서비스 제공을 위한 융합 망의 QoS 매핑에 대한 방안을 제안한다.

• 한국전자거래학회지
• /
• 제16권3호
• /
• pp.145-158
• /
• 2011

최근 스마트폰 사용의 급속한 확산은 국내외 무선망 사업자들에게 기회와 과제를 동시에 제시하고 있다. 기존의 음성 통신 시장의 정체라는 문제를 무선 데이터 시장의 확대를 통해 해결할 수 있다는 중요한 기회와 함께 폭발적으로 증가하는 거대한 데이터 트래픽을 수용할 수 있도록 고효율 무선가입자망을 새로 구축해야하는 도전 과제를 맞고 있는 것이다. 본격적인 네트워크 경쟁 시대를 맞아 무선망 사업자들 간에는 LTE 주도의 4G 네트워크 조기 구축 전략과 3G 및 4G 혼합형 망고도화 전략간 경쟁이 치열하게 전개되고 있다. 사업자의 미래 네트워크 전략으로 LTE 조기도입에 따른 4G 단일 망 위주의 전략이 성공적일지 HSPA+, WiFi, 클라우드 컴퓨팅 등 대체 망을 통한 복합적 망고도화 전략이 성공적일지에 대한 판단이 중요한 시점이다. 향후 현 시점에서의 판단과는 다른 의외의 결과가 나올 수도 있음은 물론이다. 본 논문에서는 이러한 국내외 통신산업의 망고도화 동향과 추이를 살펴보고 다양한 망고도화 이행 전략을 비교 분석하여 앞으로의 4G 네트워크 경쟁에 대한 전망과 효율적 운영 방안을 도출하고자 한다.

• 전자통신동향분석
• /
• 제38권2호
• /
• pp.46-55
• /
• 2023

Extended reality (XR) provides an immersive virtual experience by using various media. The XR virtual environment enables interactions between the real and virtual worlds in virtual, augmented, and mixed reality scenarios. XR is being used in various areas such as industry, medical care, road transportation, gaming, education, and culture. XR and multimedia enhancement are important business scenarios for fifth-generation (5G) mobile networks. As users' demand for emerging media services gradually increases, enhancements in networks should be implemented for delivering multimedia services such as XR. We describe related standardization trends and requirements of the XR service in 5G mobile networks. We also discuss technological enhancements for 5G mobile networks as specified by the 3GPP SA2 working group.

• International journal of advanced smart convergence
• /
• 제11권3호
• /
• pp.17-22
• /
• 2022

As the sixth generation (6G) promising technique, intelligent reflecting surface (IRS) has recently attracted much attention. The IRS based wireless communication is expected to deploy the upcoming 6G mobile networks, to increase energy and spectrum efficiency in the fifth generation (5G) wireless networks. In this paper, we compare the bit-error rate (BER) performances for phase-shift schemes of IRS non-orthogonal multiple access (NOMA). First, we derive a BER expression for the equalizing phase-shift scheme in IRS-NOMA networks. Then we compare the BER of the equalizing phase-shift scheme to that of the identical phase-shift scheme in IRS-NOMA networks, and show the BER improvement of the equalizing phase-shift scheme IRS NOMA over the identical phase-shift scheme IRS NOMA. Furthermore, we also validate the proposed analytical BER for the equalizing phase-shift scheme in IRS-NOMA by Monte Carlo simulations, and demonstrate that they well match each other.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
• /
• pp.237-242
• /
• 2008

A number of wireless technologies have been implemented, but each technology has its limitation in terms of coverage and bandwidth. WLAN and 3G cellular network has emerged to be a complementary platform for wireless data communications. However, the mobility of roaming terminals in heterogeneous networks poses several risks. To maintain secure communications in universal roaming, the effective authentication must be implemented. The focus of this paper is on analysis of authentication architecture involved in integrated WLAN/3G networks.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
• /
• 제1권1호
• /
• pp.35-46
• /
• 2012

무선 통신 시스템의 개발에 의해 한 지역에서 3G 네트워크와 WLAN, 무선 광대역 네트워크와 같은 여러 무선 네트워크 접속 기술들이 사용 가능하게 되었다. 이러한 기술의 발달로 사용자는 저속 또는 고속으로 이동하는 환경과 AP(Access Point)간 거리 변화에 따른 다양한 환경에서 차량용 모바일 네트워크 환경을 경험하고 있다. 본 논문에서는 다양한 환경 변화에 따른 네트워크 성능 문제를 다루고 있다. 전송 시간이나 전송 비용을 최소화하는데 중점을 두고, 퍼지 로직을 적용해 주변환경 요소에 따른 성능 평가를 한다. 먼저 WLAN과 고정 거리간 AP를 가지는 3G 네트워크로 구성된 환경과 WLAN과 무작위 거리에 있는 AP(Access Points)를 가지는 3G 네트워크로 구성된 환경, 그리고 위 두 환경에서 차량용 Ad hoc 네트워크를 사용한 환경에서의 성능을 분석한다. 이는 V2I(Vehicle to Infrastructure) / V2V(Vehicle to Vehicle) 환경을 가정한 상황이다. 퍼지 로직을 적용한 연구 결과를 바탕으로 차량의 이동 속도와 APs간의 거리에 따른 차량용 네트워크의 최적화 방향이 되는 환경을 제안한다. 제안된 알고리즘을 적용하였을 경우, V2I와 V2V환경에서 네트워크 성능은 각각 21%/ 13%가 향상되는 결과를 보였다.

• 전자통신동향분석
• /
• 제36권6호
• /
• pp.13-24
• /
• 2021

Industrial networks has been developing various technologies from fieldbus technology to industrial Ethernet and time-sensitive networking. The industry expects that the 5G mobile network will solve the diverse and highly specific industrial site requirements. Accordingly, 3GPP has been developing standard functions to provide ultra-high reliability, ultra-high speed, ultra-connection, and ultra-low latency services, and 3GPP Rel-16 began developing ultra-low latency and ultra-high reliability communication functions for 5G mobile networks to support vertical industries. In this paper, we show the related standardization trends and requirements to apply industrial IoT service scenarios to 5G mobile networks, and in particular, we introduce 5G system features and extended 5G system architecture to provide time sensitive communication and time synchronization services.