Browsing by Author "Lo, CC"

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A dynamic incentive pricing scheme for relaying services in multi-hop cellular networks
(2004)
Lin, MH
;
Lo, CC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Applying peer-to-peer communications in cellular networks to improve performance has been an active research area in recent years. Cooperation among nodes is an important prerequisite for the success of the multi-hop cellular networks. Cost savings and service availability are the primary concerns that the network provider adopts multi-hop cellular networking technology. In this paper, we present a dynamic incentive pricing scheme to maximize the revenue of the network provider. The proposed scheme adjusts the price of the feedback incentives based on the network conditions to influence the relaying capability of the network and therefore increases the revenue of the network provider. The simulation results demonstrate that the revenue can be increased by dynamically adjusting the price of the incentives for relaying services. Moreover, the proposed pricing scheme results in more revenue but does not cause higher new call blocking probability in multi-hop cellular networks.
A fault-tolerant architecture for ATM networks
(1999-10-15)
Lo, CC
;
Chiou, CY
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The asynchronous transfer mode (ATM) is the transfer mode recommended for the broad integrated service digital network (B-ISDN) by ITU-T. In this paper, we propose a self-routing fault-tolerant switching architecture for ATM networks. The proposed architecture uses subswitches and extra links to provide alternative paths; hence, can tolerate multiple faults. Analytical results show that the total number of redundant paths increases exponentially as the size of the network increases. A simulation model is developed. Simulation results indicate that the proposed architecture is much more fault-tolerant and cost-effective than those architectures found in the literature. Simulation results also illustrate that the proposed architecture still maintains a high throughput with an acceptable cell delay time, even when the number of faulty elements increases. (C) 1999 Elsevier Science B.V. All rights reserved.
A fuzzy analysis method for new-product development
(2005)
Lo, CC
;
Wang, P
;
Chao, KM
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
This paper reports a new idea-screening method for new product development (NPD) with a group of decision makers having imprecise, inconsistent and uncertain preferences. The traditional NPD analysis method determines the solution using the membership function of the fuzzy set which cannot treat the negative evidence. The advantage of vague sets with the capability of representing negative evidences supports the decision makers with ability of modeling uncertain objects. In this paper, we present a new method for new-product screening in the NPD process by relaxing a number of assumptions so that imprecise, inconsistent and uncertain ratings can be considered In addition, a new similarity measure of vague sets is introduced to proceed with the ratings aggregation for a group of decision makers. From numerical illustrations, the proposed model can outperform conventional fuzzy methods. It is able to provide decision makers (DMs) with consistent information and to model the situation where vague and ill-defined information exist in the decision process.
A histogram-based moment-preserving clustering algorithm for video segmentation
(2003-10-01)
Lo, CC
;
Wang, SJ
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Video segmentation is the first step of creating video indices for a video retrieval system. A segmentation algorithm is used to identify shots from video data. In this paper, we propose a histogram-based moment-preserving (HBMP) clustering algorithm for segmenting video data. This algorithm is a hybrid of the shot change detection approach and the clustering approach. The computational results indicate that the proposed algorithm is both effective and efficient with respect to various types of video sequence. (C) 2003 Elsevier B.V. All rights reserved.
A key agreement protocol using mutual authentication for ad-hoc networks
(2005)
Lo, CC
;
Huang, CC
;
Huang, YX
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Security is the major concern on designing a communications network. As for ad-hoc networks, the security problem is much more complicate than that of conventional networks. In this paper, the problem of securely generating and distributing a group key to group members of an ad-hoc network is addressed. A key agreement protocol using mutual authentication is proposed. The idea of using the XOR operator suggested in a previous study is adopted. By using mutual authentication, the proposed protocol prevents both replay attack and password-guessing attack, which are two potential problems in the previous study. To further enhance security, a rekeying mechanism is introduced for updating the group key if there were no changes in group members. Both security and complexity analyses show that the proposed protocol is not only securer but also more efficient than other well-known key agreement protocols.
A moderated fuzzy matchmaking for web services
(2005)
Huang, CL
;
Chao, KM
;
Lo, CC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
A number of matchmaking methods have been proposed and used for various applications. However, the issues associated with matchmaking for web services that involve data repository are not well addressed by the existing methods which focus on service capabilities, interface signatures, and so on. This results from that the information and data in repository are not considered for matchmaking. In our previous work, we proposed a juzzy matchmaking framework which exploits fuzzy logic to abstract and classify the underlying data of web services as juzzy terms and rules. As a result, it increases the efficiency of the discovery of web services and allows imprecise or vague terms incorporated in the search. However, the assumption of unified (consensus) value between service providers and consumers for the service is made. In this paper, a fuzzy moderator is introduced in order to provide a tracking mechanism for consumers' feedbacks and moderate their values.
A multiobjective hybrid genetic algorithm for the capacitated multipoint network design problem
(2000-06-01)
Lo, CC
;
Chang, WH
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The capacitated multipoint network design problem (CMNDP) is NP-complete, In this paper, a hybrid genetic algorithm for CMNDP is proposed. The multiobjective hybrid genetic algorithm (MOHGA) differs from other genetic algorithms (GA's) mainly in its selection procedure. The concept of subpopulation is used in MOHGA, Four subpopulations are generated according to the elitism reservation strategy, the shifting Prufer vector, the stochastic universal sampling, and the complete random method, respectively, Mixing these four subpopulations produces the next generation population. The MOHGA can effectively search the feasible solution space due to population diversity, The MOHGA has been applied to CMNDP. By examining computational and analytical results, we notice that the MOHGA can find most nondominated solutions and is much more effective and efficient than other multiobjective GA's.
A novel approach of backup path reservation for survivable high-speed networks
(2003-03-01)
Lo, CC
;
Chuang, BW
;
交大名義發表
;
National Chiao Tung University
For high-speed networks, a restoration mechanism based on backup path provides a, means for assuring their survivability. In this article, we propose a two-phase BP reservation mechanism for high-speed networks. In the admission phase, a pair of working path and backup path is selected from the provisioned sets of WPs and BPs. In the adjustment phase, if backup capacity utilization exceeds the preset threshold, BP assignments are rearranged to optimize the usage of backup capacity. A mathematical model is formulated to verify the quality of the optimized solutions. Computational experiments indicate that the proposed mechanism significantly reduces the consumption of backup capacity while still maintaining a high degree of survivability. Moreover, experiments show that the optimized solutions obtained are on average within 3.6 percent of optimal.
A prepaid service-based charging and billing protocol for Internet services
(2002)
Lo, CC
;
Lin, MH
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The explosive growth of Internet services makes ISPs necessitate a flexible and practical service-based charging model to promote various services in an increasingly competitive market. Much research has focused on transport-based charging that meters traffic volume or time duration as usage parameters. However, charging only for the transport negates the perceived value of the content and neglects the atomic nature of some services. In this paper, we present a prepaid service-based charging and billing protocol extended from the Remote Access Dial-In User Service (RADIUS) protocol because of its extensibility and deployments by a wide range of existing vendors. The proposed charging model classifies services into atomic service and divisible service. The atomic service is charged all or nothing based on the transmission status; the divisible service is charged in proportion to the service duration. This research also suggests charging Internet services by prepaid business model. The prepaid model attracts both the operators and the customers. The operators have the ability to monitor subscribers spending and prevent subscribers from using services they cannot afford real-time. The customers have the opportunity to control their own spending and take a limited amount of risk.
A quality of relay-based incentive pricing scheme for relaying services in multi-hop cellular networks
(2005)
Lin, MH
;
Lo, CC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Cooperation among nodes is a critical prerequisite for the success of the relaying ad-hoe networks. Providing incentives for mobile nodes to forward data packets for others has received increasing attention. In this paper, we propose a Quality of Relay (QoR)-based pricing scheme to determine the price of the feedback incentives for intermediate nodes based on the individual importance of each mobile node contributing to successful hop-by-hop connections. Simulation results indicate that the QoR-based pricing scheme results in higher service availability than the fixed-rate pricing scheme under different relationships between price of feedback and willingness of forwarding packets. Moreover, the proposed pricing scheme shifts incentives from the nodes of low importance to the nodes of high importance in the networks so that it enhances service availability with only a slight increase in relaying costs.
Alarm correlation for congestion diagnosis in ATM networks
(1996)
Lin, YD
;
Yang, RK
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Lo, CC
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資訊工程學系
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Department of Computer Science
An adaptive survivability admission control mechanism using backup VPs for self-healing ATM networks
(2002)
Lo, CC
;
Chuang, BW
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Restoration mechanism based on backup capacity provides a solution for assuring network survivability. In this paper we propose an adaptive survivability admission control mechanism using back-zip virtual paths for self-healing Asynchronous Transfer Mode (ATM) networks. Working virtual paths (WVPs) and backup virtual paths (BVPs) are configured during the network design phase. For each call request, the proposed mechanism selects a pair of WVP and BVP, followed by bandwidth reservation for the pair only if both the WVP and the BVP selected succeed in the call admission Control. A backup dependency, matrix (BDM) is suggested for recording the most up-to-date information of backup capacity, required on a link for restoring a failure 017 other links. However backup capacity, actually, reserved on a link is shared by all BVPs passing the same link. This "sharing" concept substantially, reduces the amount of backup capacity, required The selection of BTT uses the BDM so as to make the selection adaptive to the current traffic loads on the network Two BVP selection methods, min-cost and min-expectation, are proposed, The min-cost strategy, increases network utilization while maintaining full survivability, under a single link failure. On the contra 3,, the min-expectation strategy, enhances network survivability, by slightly, reducing network utilization. Simulation results indicate that the proposed mechanism guarantees a 100 percent survivability, under any single link failure and supports an zip to 83 percent survivability, under double link failures, Above all, this mechanism not only, acquires desired survivability, but also at the same time keeps satisfactory, network utilization.
An XCS-based intelligent searching model for cross-organization identity management in web service
(2004)
Lo, CC
;
Lin, WL
;
Wu, J
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資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Internet services in distributive organization are normally built on an open network environment. In the environment internet service provisioning cannot be expected executing in a single close organization [1]. Identity management in cross-organization becomes an issue for handling Internet service and distributive business process. The "identity" in cross-organization web service is defined as global identity rather than private identity from client. Global identity searching; table that registers all related service organization is the normal way we used to [2]. Through global identity searching table the target service organization can be looked up directly. For some business program, however, global identity is not necessary registered in specific service organization, e.g. IMSI (International Mobile Subscriber Identification) registration in NP (Number Portability) Service [3], for instance. In NP Service each IMSI can be re-assigned to different mobile service provider if the IMSI apply the re-assigmnent. In the example about IMSI in NP service mentioned above, if there is an internet service will be executed according to identity management with IMSI, then it will be a challenge to find the organization for available IMSI in very short response time. To dynamically re-assign a IMSI in different mobile service provider, the traditional global identity searching table will not be practical due to frequently changing the registration of IMSI in different service provider. To give an intelligent searching model for cross-organization global identity management is a better way than a static global identity searching table management in Web service. In this article the XCS (eXtended Classifier System) classifier system [4] will be proposed as the kernel system. With the characteristics in machine learning and rules management, the XCS-based intelligent searching model can help to predict where the web service can find the global identity in the open and cross-organization environment.
Authentication protocols for the broadband ISDN billing system
(1999-12-01)
Lo, CC
;
Yeh, YC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The broadband integrated services digital network (B-ISDN) offers a wide variety of services to its customers. From both provider's and user's perspective, a fair and flexible billing system is indispensable to the operation of B-ISDN. In this paper, we discuss different billing policies, and their corresponding authentication protocols, which can be used by the B-ISDN billing system. Flat rate and usage-based rate are two most frequently used billing policies. Because of the diversity of B-ISDN services, combining these two billing policies, along with priority pricing, is a feasible scheme for designing a B-ISDN billing system. The membership authentication protocol (MAP) and the personal authentication protocol (PAP) are proposed to support the authentication requirements of the flat rate and usage-based rate billing policies, respectively. The MAP applies the cipher block chaining (CBC) encryption in the two-party authentication protocol, while the PAP is a modified version of the station-to-station (STS) authentication protocol. Both protocols are designed in conjunction with a suggested key management method. Cryptanalysis shows that both the MAP and the PAP are very secure. Simulation results indicate that both protocols are efficient for providing mutual authentication. Together, these two protocols provide a good authentication mechanism to the B-ISDN billing system. (C) 1999 Elsevier Science B.V. All rights reserved.
Diminishing capacity requirement for mobility database in wireless ATM
(2004-04-01)
Sue, KL
;
Lo, CC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
In wireless ATM, Visitor Location Register (VLR) is the database that supports mobility management. In case the number of roaming users exceeds the VLR supports, the arriving users cannot receive any service. To solve the problem, the Random Replacement (RR) policy randomly selects a victim record in VLR to be replaced with the record of the arriving user. The quality of services for the victim user will certainly drop. Therefore, the proportion of affected users is not allowed to exceed a tolerable threshold. Apparently, VLR size is the key factor of the threshold. The cost for maintaining a VLR increases significantly as its size grows. So, how to utilize the capacity efficiently is an important issue in VLR planning. We propose a Second Chance Replacement (SCR.) policy to reduce the requirements for VLR capacity. As compared with the RR policy, the discrete-event simulation results show that the SCR policy can save 2.5% to 28% VLR size under various QoS thresholds.
Effect of process parameters on coating quality in surface coating processes
(2006)
Jou, M
;
Lo, CC
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機械工程學系
;
Department of Mechanical Engineering
Coating technologies are widely used in manufacturing processes, to prevent products from deterioration due to the actions of water, air, or an acid, to improve the artistic functions of product. In advance of nano-technologies, the geometry of coating particles will be fabricated as designed. Therefore, the effects of the geometry of materials on the coating quality should be considered in manufacturing processes. Surface roughness is one of the major indicators of coating quality. The correlation of geometry of coating materials and surface roughness on the performance of coated electrodes is presented in this paper. Three types of geometries are analyzed which are spherical particles, uniformly distributed columns, and random types. Besides the geometry of coating materials, the impact force resulting from spray jet will alter the surface roughness and is one of the important factors to coating quality. Therefore, the stability of coating jet is also studied. The findings show that high frequency waves can be added into the flow to get neutrally stable condition which will improve the stability of impact force.
Evaluation of information security related risks of an organization - The application of the multi-criteria decision-making method
(2003)
Guan, BC
;
Lo, CC
;
Wang, P
;
Hwang, JS
;
資訊管理與財務金融系註：原資管所+財金所
In the wake of the fast popularization of information and the rise of electronic commerce, information security is gaining much attention. How to perform the evaluation of the value of assets, how to perform the analysis of the risks associated with assets, and how to protect information assets from sabotage, theft and tamper are important topics in the study of the management of information security. This research addresses the aspects of confidentiality, integrity and availability of information and applies the Analytic Hierarchy Process (AHP) to consolidate expert's opinions on information risks, in order to construct an integrated framework for risk analysis. The BS7799 standard and the risk level matrix(RLM) are used accordingly to evaluate the effectiveness of and to categorize the risk management measures and to create a complete model for the assessment of information assets related risks. Finally, the research results are verified by a case study. The results can be used by organizations as references for information security planning and management process improvements.
N-class replacement policy for resolving mobility database overflow
(2003)
Sue, KL
;
Lo, CC
;
交大名義發表
;
National Chiao Tung University
Visitor Location Register (VLR) may overflow due to the limited capacity. By replacing an existing record, the overflow users can still receive services. The most-idle replacement (MR) policy was proposed to improve the performance or the random replacement (RR) policy. The MR policy seems to he optimum and outperforms the RR policy significantly. However, the MR policy has potential limitations. Accordingly, we propose the N-class replacement (NR) policy to overcome the drawbacks. Moreover, the simulation results show that the NR policy outperforms the MR policy in most scenarios investigated in our study. As N increases, the improvement becomes more considerable.
Overflow control in mobile communication using N-class replacement
(2003-01-23)
Sue, KL
;
Lo, CC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
A strategy called N-class replacement (NR) policy is proposed to overcome visitor location register (VLR) overflow in a mobile communication system. The NR policy requires only few bits in the VLR record. It is feasible for separated VLR databases in real mobile networks. For the rate of excellent replacement, the simulation results show that the NR policy outperforms currently proposed policies.
QoS provisioning in handoff algorithms for wireless LAN
(1998)
Lo, CC
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Lin, MH
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The performance of the handoff algorithm is the primary concern for supporting mobile devices with roaming capability in wireless communications. The IEEE 802.11 standard for wireless local area networks(LANs) recommends carrier sense multiple access with collision avoidance(CSMA/CA) as the medium access control(MAC) protocol. The contention-based CSMA/CA access mechanism is sensitive to the traffic load whereas the assignment-based access mechanism used by wireless telephone networks is not. Heavy traffic load in wireless LANs causes significant degradation of network performance. Thus conventional handoff algorithms employed in wireless telephone networks are not applicable to wireless LANs. In this paper, after examining existing handoff algorithms for wireless communications, we propose a handoff algorithm for wireless LANs. This algorithm considers traffic load as an important factor for initiating handoff. In normal traffic load, signal strength measurements from various access points are used the same as conventional handoff algorithms. However, in heavy traffic load, the hysteresis margin and the absolute threshold of traffic load are taken into account A simulation model is developed to study the performance of the proposed algorithm. Simulation results indicate that the proposed algorithm significantly reduces the call dropping probability. Moreover, the relationship between QoS parameters and handoff initiation criteria is analyzed. Analytical results show how handoff initiation criteria might be set in accordance with the quality of services requested by users.