• Journal of KIISE:Information Networking
• /
• v.37 no.2
• /
• pp.94-98
• /
• 2010

In this paper, we formalize a new adaptive online price control scheme based on the Stackelberg game model. By using the hierarchical interaction strategy, control decisions in each mechanism act cooperatively and collaborate with each other to satisfy conflicting performance criteria. In addition, our dynamic online approach is practical for real network implementation. With a simulation study, the proposed scheme can adaptively adjust the network price to approximate an optimized solution under widely diverse network situations.

• Advances in Computational Design
• /
• v.3 no.1
• /
• pp.35-47
• /
• 2018

Design of settlement space is a complicated process while reasonable spatial layout bears great significance on the development and resource allocation of a settlement. The study proposes a weighted L-system generation algorithm based on CA (Cellular Automation) model which tags the spatial attributes of cells through changes in their state during the evolution of CA and thus identifies the spatial growth mode of a settlement. The entrance area of the Caidian Botanical and Animal Garden is used a case study for the model. A design method is proposed which starts from the internal logics of spatial generation, explores possibility of spatial rules and realizes the quantitative analysis and dynamic control of the design process. Taking a top-down approach, the design method takes into account the site information, studies the spatial generation mechanism of settlements and further presents a engine for the generation of multiple layout proposals based on different rules. A optimal solution is acquired using GA (Genetic Algorithm) which generates a settlement spatial layout carrying site information and dynamically linked to the surround environment. The study aims to propose a design method to optimize the spatial layout of the complex settlement system based on parametric generation.

• Proceedings of the Korean Information Science Society Conference
• /
• 2011.06d
• /
• pp.137-140
• /
• 2011

최근 활발하게 연구되고 있는 4G 이동 통신 시스템의 하나인 LTE-Advanced 시스템에서 릴레이 기법은 주요 기술로써 고려되고 있다. 릴레이 기법을 도입함으로써 LTE-Advanced 시스템은 셀 가장자리 유저들에게 좋은 성능의 서비스를 제공할 수 있을 뿐 아니라 셀 커버리지를 늘릴 수 있을 것으로 기대된다. 하지만 LTE-Advanced 시스템에 릴레이 기술을 도입하는 구체적인 기법은 아직 연구되지 못하고 있다. 이러한 상황에서 우리는 기존의 직교 할당 방식과 중첩 할당 방식을 이용하여 릴레이 기법을 도입시 새로운 자원 할당 방법을 제안할 것이다. 제안 기법의 기본 아이디어는 서비스 지역에 진입한 단말이 채널 정보를 이용하여 eNB(eNodeB)로 접속할지 RS(Relay Station)로 접속할지를 결정한다. 기존의 직교 할당 방식과 중첩 할당 방식을 그대로 적용하는 경우와 비교하여 우리가 새로 제안하는 자원 할당 기법은 전송률 뿐만 아니라 공정성 측면에서도 우수한 성능을 나타낸다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.140-143
• /
• 2015

클라우드 컴퓨팅에서 가상화 기술은 단일 물리 자원을 논리적인 자원으로 분할해 다수의 시스템이 병행적으로 운용될 수 있는 환경을 구축하여 준다. 이에 컨테이너 기술 또한 프로세스의 격리를 이용해서 가상화와 같은 병행 수행 환경을 제공한다. 게다가 컨테이너 기술은 하드웨어를 추상화하는 절차가 없기 때문에 기존의 가상화 기술에 비해 오버헤드가 현저히 작다. 따라서 기존의 하이퍼바이저 자리를 대체하기 위한 수단으로 컨테이너 기술의 가능성이 점쳐지고 있다. 본 논문에서는 상용화 된 컨테이너 기술인 도커를 기존의 클라우드-가상화 환경에 도입하였을 때 발생되는 문제를 분석하여 해결 방안을 제안하고 실험을 통해 그 효과를 비교하였다. 기존의 도커는 정적 자원 할당만을 지원하며 이는 클라우드 환경에서 급격한 변화에 유연하게 대처하지 못한다는 단점을 가지고 있다. 따라서 도커에 동적 자원 할당 기술을 적용하여 기존의 단점을 보완하고 클라우드 환경에서 컨테이너 기술의 운영 효율성을 제고한다.

• International conference on construction engineering and project management
• /
• 2015.10a
• /
• pp.639-640
• /
• 2015

Traditional construction planning based on historical data and heuristic adjustment can no longer incorporate all the operational details and guarantee the expected performance. The variation between the expected and the actual production leads to cost overruns or delay. Although predicting reliable productivity on construction site is getting more important, the difficulty of this increases. In this regard, this paper suggested to develop BIM-integrated simulation framework. This framework could predict productivity dynamics by considering factors affecting on construction productivity at operational phase. We developed the following processes; 1) enabling a BIM model to produce input data for simulation; 2) developing the construction operation simulation; 3) running simulation using BIM data and obtaining productivity results. The BIM-integrated simulation framework was tested with structural steel erection model because steel erection work is one of the most critical process influencing on the whole construction budget and duration. We could improve to predict more dynamic productivity from this framework, and this reliable productivity helps construction managers to optimize resource allocation, increase schedule reliability, save storage cost, and reduce material loss.

• Journal of Communications and Networks
• /
• v.13 no.6
• /
• pp.664-677
• /
• 2011

In order to control interference and improve spectrum efficiency in the femtocell and macrocell overlaid system (FMOS), we propose a joint frequency bandwidth dynamic division, clustering and power control algorithm (JFCPA) for orthogonal-frequency-division-multiple access-based downlink FMOS. The overall system bandwidth is divided into three bands, and the macro-cellular coverage is divided into two areas according to the intensity of the interference from the macro base station to the femtocells, which are dynamically determined by using the JFCPA. A cluster is taken as the unit for frequency reuse among femtocells. We map the problem of clustering to the MAX k-CUT problem with the aim of eliminating the inter-femtocell collision interference, which is solved by a graph-based heuristic algorithm. Frequency bandwidth sharing or splitting between the femtocell tier and the macrocell tier is determined by a step-migration-algorithm-based power control. Simulations conducted to demonstrate the effectiveness of our proposed algorithm showed the frequency-reuse probability of the FMOS reuse band above 97.6% and at least 70% of the frequency bandwidth available for the macrocell tier, which means that the co-tier and the cross-tier interference were effectively controlled. Thus, high spectrum efficiency was achieved. The simulation results also clarified that the planning of frequency resource allocation in FMOS should take into account both the spatial density of femtocells and the interference suffered by them. Statistical results from our simulations also provide guidelines for actual FMOS planning.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.6
• /
• pp.187-193
• /
• 2015

The ICT healing platform sets a couple of goals including preventing chronic diseases and sending out early disease warnings based on personal information such as bio-signals and life habits. The 2-step open system(TOS) had a relay designed between the healing platform and the storage of personal health data. It also took into account a publish/subscribe(pub/sub) service based on large-scale connections to transmit(monitor) the data processing process in real time. In the early design of TOS pub/sub, however, the same buffers were allocated regardless of connection idling and type of message in order to encode connection messages into a deflate algorithm. Proposed in this study, the dynamic buffer allocation was performed as follows: the message transmission type of each connection was first put to queuing; each queue was extracted for its feature, computed, and converted into vector through tf-idf, then being entered into a k-means cluster and forming a cluster; connections categorized under a certain cluster would re-allocate the resources according to the resource table of the cluster; the centroid of each cluster would select a queuing pattern to represent the cluster in advance and present it as a resource reference table(encoding efficiency by the buffer sizes); and the proposed design would perform trade-off between the calculation resources and the network bandwidth for cluster and feature calculations to efficiently allocate the encoding buffer resources of TOS to the network connections, thus contributing to the increased tps(number of real-time data processing and monitoring connections per unit hour) of TOS.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.10
• /
• pp.3182-3194
• /
• 2000

It is strongly beliefed that Video on Demand(VOD) will become one of the most promising services in Broadband Integrated Services Digital Network(B-ISDN) for the nest generation VOD service can be classified into two types of services 'Near VOD(NVOD) and Interactive VOD(IVOD). For both services, some video servers should be installed at some nodes(especially, at the root node for NVOD service) in the tree structued VOD network,so that each node with video server stores video programs and distribules stored programs to customers. We consider thre kinds of cost.a program transmission cost, a program storage cost, and a video server installation cost. There exists a trade-off relationship among those three costs according to locationsl of video servers and the kinds of programs stord at each video server. Given a tree structured VOD network, and the total number of programs being served in the network, the resource allocation problem in a VOD network providing both IVOD and NVOD services is to determine where to install video servers for IVOD service, which and how many programs should be stored at each video server for both IVOD and NVOD services, so as to minunize the total cost which is the sum of three costs for both IVOD and NVOD services. In this paper we develop an efficient cynamic programming algorithm for solving the problem. We also implement the algorithm based on a service policy assumed in this paper.

• Journal of KIISE:Computer Systems and Theory
• /
• v.34 no.11
• /
• pp.572-580
• /
• 2007

Wireless sensor networks are sensing, computing and communication infrastructures that allow us to monitor, instrument, observe, and respond to phenomena in the harsh environment. Generally, the wireless sensor networks are composed of many deployed sensor nodes that were designed to be very cost-efficient in terms of production cost. For example, UC Berkeley's MICA motes have only 8-bit CPU, 4KB RAM, and 128KB FLASH memory space. Therefore, sensor operating systems that run on the sensor nodes should be able to operate efficiently in terms of the resource management. In this paper, we present a dynamic threads stack management scheme for space-constrained and multi-threaded sensor operating systems. In this scheme, the necessary stack space of each function is measured on compile-time. Then, the information is used to dynamically allocate and release each function's stack space on run-time. It was implemented in Nano-Qplus sensor operating system. Our experimental results show that the proposed scheme outperforms the existing fixed-size stack allocation mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.7
• /
• pp.1369-1376
• /
• 2015

A wireless bridge is essential to transmit control and managing information to sensors or instruments from a central integrated ship area network station. In this paper, a WiMedia Distributed-MAC(D-MAC) protocol is adopted for development of a seamless N-Screen wireless service in Indoor and Ship Area Networks. Furthermore, to provide the OSMU(One Source Multi Use) N-screen service through P2P streaming in the seamless D-MAC protocol, a Dynamic Threshold-based Multicast(DTM) technology is proposed and analyzed. For this technology, a new Hard/Soft Vertical Region(HVR-SVR) based time slot allocation and a multicast resource reservation scheme are combined. From simulation results, proposed DTM scheme expands the number of time slots available for unicast and multicast realtime N-Screen reservations with various service time interval requests. Furthermore, it enhances performances in vewpoints of realtime N-Screen data reservation conflict and throughput.