• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.5
• /
• pp.491-498
• /
• 2016

An ACL(: Access List), a list that determines network access, is used for the security of the network. An ACL if applied to a interface of router can filter particular packets. Also it can block or allow the access of certain unauthorized IPs or ports, based on the source address, destination address, and TCP/UDP port. This paper presents a simulation case to verify the effect of a router-based network applying Standard ACL or Extended ACL. The network was created through designing topology and then making a common virtual network using a Packet Tracer.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.1
• /
• pp.35-45
• /
• 2009

In an open environment such as Home Network, ZigBee Cluster comprising a plurality of Ato-cells is required to provide intense security over the movement of collected, measured data. Against this setting, various security issues are currently under discussion concerning master key control policies, Access Control List (ACL), and device sources, which all involve authentication between ZigBee devices. A variety of authentication methods including Hash Chain Method, token-key method, and public key infrastructure, have been previously studied, and some of them have been reflected in standard methods. In this context, this paper aims to explore whether a new method for searching for neighboring devices in order to detect device replications and Sybil attacks can be applied and extended to the field of security. The neighbor detection applied method is a method of authentication in which ACL information of new devices and that of neighbor devices are included and compared, using information on peripheral devices. Accordingly, this new method is designed to implement detection of malicious device attacks such as Sybil attacks and device replications as well as prevention of hacking. In addition, in reference to ITU-T SG17 and ZigBee Pro, the home network equipment, configured to classify the labels and rules into four categories including user's access rights, time, date, and day, is implemented. In closing, the results demonstrates that the proposed method performs significantly well compared to other existing methods in detecting malicious devices in terms of success rate and time taken.

• Journal of the Korean Arthroscopy Society
• /
• v.9 no.2
• /
• pp.143-147
• /
• 2005

Purpose: In case of anterior cruciate ligament (ACL) reconstruction, graft tendon is generally fixed in tibial tunnel with knee extended. When reconstructing ACL using hamstring tendon, the authors aim to find out the effect of knee joint position during graft fixation on postoperative knee joint stability and range of motion. Materials and Methods: Prospective study was done on patients who have undergone ACL reconstruction using hamstring tendon from May 2002 to January 2003 We used Rigifix system (Mitek Product, Johnson and Johnson, USA) and Intrafix system for fixation. Thirty nine patients received ACL reconstruction during this period. Excluding 2 patients lost in the follow-up, 37 patients were analyzed. The mean follow-up period was 14 months $(13{\sim}25months)$. Knee position was decided alternatively without any bias. Clinical evaluation was based on Lachman test, pivot shift test, Lysholm score, IKDC(international knee documentation committee) assessment and side to side KT-1000 maximal manual arthrometer difference. Results: After the last follow-up, average postoperative Lysholm score was 93.1 poins(65-98points). According to IKDC score, 26 cases were normal, 10 cases were nearly normal, 1 case was abnormal and we had no case of severe abnormality. The mean difference from the normal side was 2.5 mm under maximal manual loading KT-1000 arthrometer. According to postoperative Lachman test, 32 cases were normal,2 cases were grade I and 1 case was grade II. There were 34 cases of normal, 2 cases of grade I and 1 case of grade II. When using maximal manual KT-1000 arthrometer side to side difference, the difference from the normal side while fixing the tibia at 20'knee flexion was 2.3 mm and at full extention the difference was 2.7 mm. The range of motion at postoperative 1 year showed 5 degree flexion contracture in 1 case at 20 degrees knee flexion and 10 degrees of flexion limitation was observed in 2 cases at full extension. Conclusion: When ACL reconstruction using autogenous hamstring tendon, anterior laxity showed no difference in its stability between two groups. Tibial side fixation at full extension may be helpful in preventing flexion contracture due to overconstrained graft tendon.

• Korean Journal of Cognitive Science
• /
• v.4 no.1
• /
• pp.177-212
• /
• 1993

My research is based on the parser for ill-formed input by Mellish in a paper in ACL 27th meeting Proceedings. 1989. My system is composed of two parsers:WFCP and IFCP. When WFCP fails to give the parse tree for the input sentence, the sentence is identified as ill-formed and is parsed by IFCP for error detection and recovery at the syntactic level. My system is indendent of grammatical rules. It does not take into account semantic ill-formedness. My system uses a grammar composed of 25 context-free rules. My system consistes of two major parsing strategies:top-down expection and bottem-up satisfaction. With top-down expectation. rules are retrieved under the inference condition and expaned by inactive arcs. When doing bottom-up parsing. my parser used two modes:Left-Right parsing and Right-to-Left parsing. My system repairs errors sucessfully when the input contains an omitted word or an unknown word substitued for a valid word. Left- corner and right-corner errors are more easily detected and repaired than ill-formed senteces where the error is in teh middle. The deviance note. with repair details, is kept in new inactive arcs which are generated by the error correction procedure. The implementation of my system is quite different from Mellish's. When rules are invoked. my system invokes all rules with minimal inference. My bottom up parsing strategy uses Left-to-Right mode and Right-to-Left mode. My system is bottom-up-parsing-oriented like the chart parser. Errors are repaired in two ways:using top-down hypothesis, and using Need-Chart which keeps the information of expectation and complection of expanded goals by rules. To reduce the number of top-down cycles. all rules are invoked simultaneously and this invocation information is kept in Need-Chart. This idea will be extended for the implementation of multiple error recovery system.