Browsing by Author "Chen, Ying-Yu"

Now showing 1 - 14 of 14

A new model for optimal routing and wavelength assignment with fixed-length tunnel allocation in multi granularity cross-connect WDM networks
(2005)
Chen, Chien
;
Kuo, Xiu-Jia
;
Chen, Ying-Yu
;
Lo, Tse-Yu
;
資訊工程學系
Multi-granularity Optical Cross-Connect (MG-OXC) has been proposed to provide a cost-efficient way to support the growing demand for bandwidth. In the MG-OXC networks, consecutive wavelengths are bundled to form a tunnel and then switched as a single unit. Network resources at the intermediate nodes on the route of a tunnel, including switching fabrics and multiplexers, can thus be reduced. In this paper we consider the problem of routing and wavelength assignment (RWA) with tunnel allocation in MG-OXC networks. Given a set of static lightpath requests, our problem is to (a) allocate a set of fixed-length tunnels (b) find routes from the source nodes to their respective destination nodes, and (c) assign wavelengths to theses route. The objective here is to minimize the blocking probability. Furthermore, we extend our work for the dynamic RWA problem. Given a historical traffic matrix, the dynamic RWA problem is how to build a set of tunnels offline to accommodate the future dynamic lightpath requests in such a way that the blocking probability can be minimized. In order to utilize the wavelength ports and fibers efficiently, each tunnel established should follow a tunnel length constraint which could be equal to the average network hop distance. Based on this criterion, a novel graph model is proposed [7] in which edges are added only for the node pairs whose hop distance follow the tunnel length constraint to form an auxiliary graph. In this paper, we suggest a 0/1 Integer Linear Programming (ILP) formulaion for RWA with tunnel allocation in MG-OXC networks under the tunnel length constraint. The previous auxiliary graph model is extended to a layered auxiliary graph model to facilitate the formulation. We compare the performance of different heuristics, including CB-STA [1], WTA and PCWTA [7], to the ILP solution. The simulation results show that PC-WTA and WTA outperforms CB-STA in all switching type combinations and network topologies, and they are very close to the optimal value calculated from our ILP formulation.
An Integrated Edge and Fog System for Future Communication Networks
(2018-01-01)
Kuo, Ping-Heng
;
Mourad, Alain
;
Lu, Chenguang
;
Berg, Miguel
;
Duquennoy, Simon
Put together, the edge and fog form a large diverse pool of computing and networking resources from different owners that can be leveraged towards low latency applications as well as for alleviating high traffic volume in future networks including 5G and beyond. This paper sets out a framework for the integration of edge and fog computing and networking leveraging on ongoing specifications by ETSI MEC ISG and the OpenFog Consortium. It also presents the technological gaps that need to be addressed before such an integrated solution can be developed. These noticeably include challenges relating to the volatility of resources, heterogeneity of underlying technologies, virtualization of devices, and security issues. The framework presented is a Launchpad for a complete solution under development by the 5G-CORAL consortium.
An MIMO Configuration Mode and MCS Level Selection Scheme by Fuzzy Q-Learning for HSPA(+) Systems
(2012-07-01)
Chung, Wen-Ching
;
Chang, Chung-Ju
;
Feng, Kai-Ten
;
Chen, Ying-Yu
;
電機工程學系
In this paper, we propose a fuzzy Q-learning-based MIMO configuration mode and MCS level (FQL-MOMS) selection scheme for high speed packet access evolution (HSPA(+)) systems. The FQL-MOMS selection scheme intends to enhance the system throughput under the block error rate (BLER) requirement guarantee. It will determine an appropriate MIMO configuration mode and MCS (modulation and coding scheme) level for packet data transmission in HSPA(+) systems, under the situations that the channel status is varying and the channel quality indication (CQI) has report delay. The FQL-MOMS scheme considers not only the reported CQI and the last transmission result but also the BLER performance metric and the transmission efficiency. Moreover, it is effectively configured, where the fuzzy rules and the reinforcement signals for the Q-learning algorithm are sophisticatedly designed. Simulation results show that the proposed FQL-MOMS scheme increases the system throughput by up to 49.3 and 35.9 percent, compared to the conventional adaptive threshold selection (ATS) scheme [12] and the Q-HARQ scheme [14], respectively, under the BLER requirement fulfillment.
"Bounded & Nuanced": Designing Mobile Technology for Children and Parents
(2019-01-01)
Chen, Ying-Yu
;
Tseng, Yuan-Chi
;
Chen, Chia-Yu
;
Yuan, Tina
;
交大名義發表
In this workshop, we intend to bring scholars and practitioners of MobileHCI conference who are interested in designing technology use for children and their parents. Parents are concerned with technology addiction for their children but generally feel loss of control in the ubiquity of mobile devices. We believe mobile design community can contribute meaningful ideas in this space. The goal of this workshop is for participants to co-develop a shared vocabulary and framework for "designing bounded and nuanced technology" as a strategy to be deployed in conceiving and implementing mobile technologies for family use.
Channel Assignment and Routing for Multi-Channel Wireless Mesh Networks Using Simulated Annealing
(2006)
Chen, Ying-Yu
;
Liu, Shang-Chun
;
Chen, Chien
;
資訊工程學系
;
Department of Computer Science
Wireless mesh networks (WMNs) are emerging as a favorable technology for last-mile Internet access. Nodes in WMNs can be equipped with multiple interfaces which work in different channels to increase the available bandwidth. However, efficient channel assignment schemes are still needed due to the interference effect and the limited number of orthogonal channels. In this paper, we consider the channel assignment and routing for dynamic traffic in WMNs. We adopt the static channel assignment strategy to the network interfaces. The problem is simplified into two sequential stages. The first is to assign channels to interfaces while the second is to determine the route for each coming traffic demand. We propose a Mixed Integer Linear Programming (MILP) formulation to the problem and develop a simulated annealing based channel assignment algorithm for the channel assignment. The shortest path routing is adopted for the dynamic traffic. Simulation results show the network throughput and blocking probability under different network scenarios.
Design and characterization of a novel amphiphilic chitosan nanocapsule-based thermo-gelling biogel with sustained in vivo release of the hydrophilic anti-epilepsy drug ethosuximide
(2012-08-10)
Hsiao, Meng-Hsuan
;
Larsson, Mikael
;
Larsson, Anette
;
Evenbratt, Hanne
;
Chen, Ying-Yu
Thermo-gelling injectable nanogels, with no burst release of loaded drug, were prepared by a simple route by combining self assembled nanocapsules of amphiphilically modified chitosan with glycerophosphate di-sodium salt and glycerol. The potential as a depot drug delivery system was demonstrated in vivo through the therapeutic effect of ethosuximide (ESM) loaded nanogels, suppressing spike wave discharges (SWDs) in Long Evan rat model. Simultaneously clearance of gels from the site of administration was monitored non-invasively using MRI. The gel structure was characterized using TEM and SEM, confirming the gels to be an assembly of nanocapsules and using two-photon microscopy to visualize the network structure. In vitro drug release studies using ESM revealed that the nanogels exhibited extended, mostly Fickian release. Finally, all investigated formulations displayed excellent cytotoxicity data determined by MTT assay using human retinal pigmented epithelium cells. All presented properties are highly desirable for injectable depot gels for drug delivery. (c) 2012 Elsevier B.V. All rights reserved.
Experience in developing a high availability and continuous TCP using OpenAIS and TCPCP
(2007)
Chen, Ying-Yu
;
Chen, Chien
;
Huang, Chia-Yuan
;
資訊工程學系
;
Department of Computer Science
It has become one of the basic requirements for the service providers to deliver highly available services to meet the customers\' critical needs. However, a highly available service does not guarantee that the service is delivered continuously from the user\'s point of view. In this paper, we share the experience of developing high-availability and continuous TCP using open source OpenAIS and TCPCP/TCPCP2. We describe the main system design for building such systems. We specifically discuss two of the problems that need to be overcome under this kind of design model. For each problem and its corresponding resolution, we show a simulation using ns2 simulator, which provides a deeper insight into the problems for further studies. We also develop a simple application which uses OpenAIS and TCPCP2 to achieve its high availability and service continuity. The results indicate that a high availability and service continuity service can be obtained with minor degradation in performance.
HARQ Control Scheme by Fuzzy Q-Learning for HSPA(+)
(2011)
Chung, Wen-Ching
;
Chen, Ying-Yu
;
Chang, Chung-Ju
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, we propose a hybrid automatic repeat request (HARQ) control scheme by using fuzzy Q-learning algorithm for high speed packet access evolution (HSPA(+)) systems. The challenge of the HARQ control in HSPA(+) systems is the selection of MIMO (multiple-input multiple-output) configuration mode and MCS (modulation and coding scheme) level for new data transmission of HARQ, under the situation that the channel quality indication has report delay. The fuzzy Q-learning-based HARQ (FQL-HARQ) scheme can determine an appropriate MIMO configuration mode and MCS level for new data transmission so as to maximize the system throughput under the guaranteed block error rate (BLER) requirement. Simulation results show that, the proposed FQL-HARQ scheme increases the system throughput by up to 70.09% as compared to the conventional adaptive threshold method [4].
Impact of Interface Constraint on Channel Assignment in Wireless Mesh Networks
(2013)
Chen, Ying-Yu
;
Chen, Chien
;
Jan, Rong-Hong
;
資訊工程學系
;
Department of Computer Science
We consider the channel assignment problem in wireless mesh networks. Due to the limited number of radio interfaces that each node is equipped with, channel assignment must ensure that the interface constraint is obeyed, i.e., the number of different channels assigned to the links incident on a node must be no greater than the number of interfaces the node is equipped with. However, interface constraint may be one of the causes that hinder the performance of some of the existing heuristics. In this paper, we use simulated annealing to solve the channel assignment problem in wireless mesh networks. We propose two neighbor generating approaches that handle the interface constraint in different ways. The first approach starts with an infeasible random solution, and by using the penalty function technique the solution finally converges to a feasible one. The second approach, on the contrary, allows only feasible solutions to be generated during the simulated annealing process. Simulations are conducted that compare our proposed simulated annealing algorithms together with a tabu-based algorithm under different network traffic scenarios. The results show that our algorithms exhibit lower network interference than the tabu-based algorithm.
Interface Constraint Aware Modeling in Wireless Mesh Networks Using Mixed Hypergraph
(2015)
Chen, Ying-Yu
;
Chen, Chien
;
資訊工程學系
;
Department of Computer Science
This paper focuses on channel assignment in wireless mesh networks. Since nodes have only a limited number of radio interfaces, channel assignment must ensure that the interface constraint is obeyed. Although many channel assignment heuristics have been proposed, the interface constraint is usually treated as a separate constraint that is not well incorporated in the heuristics themselves. In this paper, we propose a mixed hypergraph model that captures the interface constraint on nodes and the interference between links. We propose a greedy-based channel assignment algorithm that minimizes the interference between links while conforming to the interface constraint. Simulation results show that our proposed algorithm performs especially well when the number of network interface cards is small.
Multicast Routing and Channel Assignment in Wireless Mesh Networks
(2009)
Chou, Chia-Sheng
;
Chen, Chien
;
Chen, Ying-Yu
;
Jan, Rong-Hong
;
Hsieh, Cheng-Chung
This paper studies the problem of multicast routing and channel assignment in multi-channel and multi-interface wireless mesh networks. The advantage of the wireless broadcast's nature is used to reduce interference and improve network throughput. The employed network model is first described. Next, a heuristic channel assignment algorithm that makes use of the wireless broadcast's advantage is presented. Simulation results reveal that the proposed heuristic algorithm can reduce interference and increase the network throughput in multi-channel multi-interface wireless mesh networks.
Simulated annealing for interface-constrained channel assignment in wireless mesh networks
(2015-06-01)
Chen, Ying-Yu
;
Chen, Chien
;
資訊工程學系
;
Department of Computer Science
The channel assignment problem in wireless mesh networks is considered in this paper. Due to the limited number of radio interfaces that each node is equipped with, channel assignment must ensure that the interface constraint is obeyed, i.e., the number of different channels assigned to the links incident on a node must not exceed the number of interfaces the node is equipped with. However, interface constraint may be one of the causes that hinder the performance of some of the existing heuristics. In this paper, we use simulated annealing to solve the channel assignment problem in wireless mesh networks. We consider using two neighbor generating approaches that handle the interface constraint in different ways. The first approach generates random solutions that need not conform to the interface constraint. With the incorporation of a penalty function technique, the solutions gradually converge to feasible solutions. The second approach allows only feasible solutions to be generated during the simulated annealing process. Simulations are conducted that compare our proposed simulated annealing algorithms with a tabu-based algorithm under different network settings and traffic scenarios. The results show that our algorithms exhibit improved network performance over the tabu-based algorithm. (C) 2015 Elsevier B.V. All rights reserved.
Using known vectors to improve data dissemination in opportunistic networks
(2014-01-01)
Huang, Jyh-How
;
Chen, Ying-Yu
;
Tung, Li-Ping
;
Chen, Ling-Jyh
;
資訊工程學系
An opportunistic network is a type of challenged network in which contacts are intermittent, an end-to-end path rarely exists between the source and the destination, disconnection and reconnection are common occurrences, and link performance is highly variable or extreme. Conventional methods of data dissemination in opportunistic networks rely on a meta-message exchange scheme, called the summary vector (SV), to prevent redundant transmission of data bundles that already exist on receivers. We consider that the SV scheme is costly in terms of the data transmission overhead, which is unaffordable in opportunistic networks. Hence, we propose an alternative scheme, called the known vector (KV), to improve the efficiency of meta-message exchanges for data transmission in opportunistic networks. Using a comprehensive set of simulations with realistic network scenarios, we demonstrate that the KV scheme can be easily integrated into existing opportunistic network routing protocols (e.g., Epidemic and PRoPHET routing). Moreover, it can reduce the communication overhead significantly, thereby improving energy efficiency for data transmission in opportunistic networks.
Weighted Routing in Hierarchical Multi-domain SDN Controllers
(2015)
Huang, Jian-Jhong
;
Chen, Ying-Yu
;
Chen, Chien
;
Chu, Yu Huang
;
資訊工程學系
In the common implementation of software defined networking where only one controller is used, tasks required by various applications may overwhelm the controller as the network grows, leading to degradation of the network performance. Some multi-controller architectures have been proposed to remedy such scalability issue. In this paper, we present our design and implementation of a routing application under a hierarchical multi-controller architecture. In this architecture, a network is partitioned into multiple domains, each of which is managed by a dedicated local controller, which is managed by a common global controller. The routing application is executed on the local and global controllers, jointly providing a routing service for each new flow. We provide effective mechanisms to reduce the link state that should be kept by the global controller. We propose a weight function on the links so that a weighted shortest path can be found that avoids the congested links on the network. Experiments results show that our routing application in the hierarchical multi-controller architecture has a great improvement over that of the single-controller architecture in terms various performance metrics.