• Korean Journal of Remote Sensing
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• v.32 no.5
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• pp.453-469
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• 2016

Many image fusion quality assessment techniques, which include Wald's, QNR and Khan's protocols, have been proposed. A total procedure for the quality assessment has been defined as the quality assessment protocol. In this paper, we compared the performance of the three protocols using KOMPSAT-2/3/3A satellite images, and tested the applicability to the fusion quality assessment of the KOMPSAT satellite images. In addition, we compared and analyzed the strengths and weaknesses of the three protocols. We carried out the qualitative and quantitative analysis of the protocols by applying five fusion methods to the KOMPSAT test images. Then we compared the quantitative and qualitative results of the protocols from the aspects of the spectral and spatial preservations. In the Wald's protocol, the results from the qualitative and quantitative analysis were almost matched. However, the Wald's protocol had the limitations 1) that it is timeconsuming due to downsampling process and 2) that the fusion quality assessment are performed by using downsampled fusion image. The QNR protocol had an advantage that it utilizes an original image without downsampling. However, it could not find the aliasing effect of the wavelet-fused images in the spectral preservation. It means that the spectral preservation assessment of the QNR protocol might not be perfect. In the Khan's protocol, the qualitative and quantitative analysis of the spectral preservation was not matched in the wavelet fusion. This is because the fusion results were changed in the downsampling process of the fused images. Nevertheless, the Khan's protocol were superior to Wald's and QNR protocols in the spatial preservation.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.172-181
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• 2005

The latest attack type against network traffic appeared by worm and bot that are advanced in DDoS. It is difficult to detect them because they are diversified, intelligent, concealed and automated. The exisiting traffic analysis method using SNMP has a vulnerable problem; it considers normal P2P and other application program to be harmful traffic. It also has limitation that does not analyze advanced programs such as worm and bot to harmful traffic. Therefore, we analyzed harmful traffic out Protocol and Port analysis. We also classified traffic by protocol, well-known port, P2P port, existing attack port, and specification port, apply singularity weight to detect, and analyze attack availability. As a result of simulation, it is proved that it can effectively detect P2P application, worm, bot, and DDoS attack.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.683-701
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• 2012

IEEE 802.11 standard has achieved huge success in the past decade and is still under development to provide higher physical data rate and better quality of service (QoS). An important problem for the development and optimization of IEEE 802.11 networks is the modeling of the MAC layer channel access protocol. Although there are already many theoretic analysis for the 802.11 MAC protocol in the literature, most of the models focus on the saturated traffic and assume infinite buffer at the MAC layer. In this paper we develop a unified analytical model for IEEE 802.11 MAC protocol in ad hoc networks. The impacts of channel access parameters, traffic rate and buffer size at the MAC layer are modeled with the assistance of a generalized Markov chain and an M/G/1/K queue model. The performance of throughput, packet delivery delay and dropping probability can be achieved. Extensive simulations show the analytical model is highly accurate. From the analytical model it is shown that for practical buffer configuration (e.g. buffer size larger than one), we can maximize the total throughput and reduce the packet blocking probability (due to limited buffer size) and the average queuing delay to zero by effectively controlling the offered load. The average MAC layer service delay as well as its standard deviation, is also much lower than that in saturated conditions and has an upper bound. It is also observed that the optimal load is very close to the maximum achievable throughput regardless of the number of stations or buffer size. Moreover, the model is scalable for performance analysis of 802.11e in unsaturated conditions and 802.11 ad hoc networks with heterogenous traffic flows.

• Korean Journal of Radiology
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• v.21 no.4
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• pp.450-461
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• 2020

Objective: We performed a meta-analysis to evaluate the agreement of cardiac computed tomography (CT) with cardiac magnetic resonance imaging (CMRI) in the assessment of right ventricle (RV) volume and functional parameters. Materials and Methods: PubMed, EMBASE, and Cochrane library were systematically searched for studies that compared CT with CMRI as the reference standard for measurement of the following RV parameters: end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), or ejection fraction (EF). Meta-analytic methods were utilized to determine the pooled weighted bias, limits of agreement (LOA), and correlation coefficient (r) between CT and CMRI. Heterogeneity was also assessed. Subgroup analyses were performed based on the probable factors affecting measurement of RV volume: CT contrast protocol, number of CT slices, CT reconstruction interval, CT volumetry, and segmentation methods. Results: A total of 766 patients from 20 studies were included. Pooled bias and LOA were 3.1 mL (-5.7 to 11.8 mL), 3.6 mL (-4.0 to 11.2 mL), -0.4 mL (5.7 to 5.0 mL), and -1.8% (-5.7 to 2.2%) for EDV, ESV, SV, and EF, respectively. Pooled correlation coefficients were very strong for the RV parameters (r = 0.87-0.93). Heterogeneity was observed in the studies (I² > 50%, p < 0.1). In the subgroup analysis, an RV-dedicated contrast protocol, ≥ 64 CT slices, CT volumetry with the Simpson's method, and inclusion of the papillary muscle and trabeculation had a lower pooled bias and narrower LOA. Conclusion: Cardiac CT accurately measures RV volume and function, with an acceptable range of bias and LOA and strong correlation with CMRI findings. The RV-dedicated CT contrast protocol, ≥ 64 CT slices, and use of the same CT volumetry method as CMRI can improve agreement with CMRI.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.417-424
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• 2007

Mesh networks using WLAN technology have been paid attention as a key wireless access technology. However, many technical issues still exist for its successful deployment. One of those issues is the routing problem that addresses the path setup through a WLAN mesh network for the data exchanges between a station and a wired network. Since the characteristics of a WLAN mesh network can be very dynamic, the use of single routing protocol would not fit for all environments whether it is reactive or proactive. Therefore, it is required to develop an adaptive routing protocol that modifies itself according to the changes in the network parameters. As a logical first step for the development, an analytical model considering all the dynamic features of a WLAN mesh network is required to evaluate the performance of a reactive and a proactive routing scheme. In this paper, we propose an analytical model that makes us scrutinize the impact of the network and station parameters on the performance of each routing protocol. Our model includes the size of a mesh network, the density of stations, mobility of stations. and the duration of network topology change. We applied our model to the AODV that is a representative reactive routing protocol and DSDV that is a representative proactive routing protocol to analyze the tradeoff between AODV and DSDV in dynamic network environments. Our model is expected to help developing an adaptive routing protocol for a WLAN mesh network.

• Journal of Internet Computing and Services
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• v.6 no.3
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• pp.17-30
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• 2005

A PAK(Password-Authenticated Key Exchange) protocol is used as a protocol to provide both the mutual authentication and allow the communication entities to share the session key for the subsequent secure communication, using the human-memorable portable short-length password, In this paper, we propose distributed key exchange protocols applicable to a smartcard using the MTI(Matsumoto, Takashima, Imai) key distribution protocol and PAK protocol. If only one server keeps the password verification data which is used for password authentication protocol. then It could easily be compromised by an attacker, called the server-compromised attack, which results in impersonating either a user or a server, Therefore, these password verification data should be distributed among the many server using the secret sharing scheme, The Object of this paper Is to present a password-based key exchange protocol which is to allow user authentication and session key distribution, using the private key in a smartcard and a password typed by a user. Moreover, to avoid the server-compromised attack, we propose the distributee key exchange protocols using the MTI key distribution protocol, And we present the security analysis of the proposed key exchange protocol and compare the proposed protocols with the existing protocols.

• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.237-246
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• 2000

A broadband access network in B-ISDN subscriber network, plays a role of concentration or multiplexing of various subscribers into a service node. For call and connection control functions, DSS2 and B-ISUP signalling protocols are standardized for each of a subscriber side and a network node. B-BCC and B-ANCC protocol were proposed for VB5.2 interface. This interface allows dynamic control of ATM connections at the broadband access network. To establish an end-to-end ATM connection, interworking functions between VB5.2 interface's connection control protocol and the signalling protocol, are performed at the service node. A sequential interworking model and a parallel interworking model were proposed for these interworking functions. The sequential interworking model recommended by ITU-T causes an overall connection setup delay by introducing the access network, because this model proceeds the signalling protocol of network node after the response of VB5.2 interface protocol. On the other hand, the parallel interworking model proceeds the signalling protocol and the VB5.2 interface protocol simultaneously. The simultaneity of the parallel interworking model minimizes the overall connection setup delay. In this paper, we analyze and simulate above two interworking models with B-BCC or B-ANCC protocol in terms of a connection setup delay and completion ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.260-267
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• 2008

As pervious the SAR(Security Aware Routing)[10] protocol is an secure Ad Hoc network protocol that finds a secure path, it is the security routing protocol that uses the security level of nodes as the routing information. However, the SAR protocol sometimes transfers data through inefficient transmission paths because it always tries to find secure nodes for a safe transmission. Since it is a protocol based on AODV[6], it will cause transmission delay as researching of security routing path. when a node is out of the data transmission range as its battery dying or movement. Although it is possible to connection of nodes because a characteristic of the SAR protocol, the connection is not easy to reconnect when the security level of intermediate node is lower than the level requested by a source node. In this paper, we suggest the MP-SAR based on the SAR to solve the SAR protocol's problem. The MP-SAR seeks multiple secure path for maintenance of data confidentiality using the expanded secure path detection techniques based on the SAR. It can transfer data quickly and reliably by using the shortest efficient path among multiple paths. In the research result, we proved a outstanding performance of MP-SAR than the previous SAR through comparison and analysis.

• The Journal of Korean society of community based occupational therapy
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• v.8 no.3
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• pp.25-35
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• 2018

Objective : The purpose of this study was to identify changes in reading ability among children with Borderline Intelligence by applying an electronic media reading training protocol. Methods : A picture book reading training protocol was applied to 10 childrens with borderline intelligence using electronic media to improve reading skills. This protocol was performed for 10 session once a week. After the analysis of the content validity index about the protocol presented in this study, this prococol was applied to the subjects. To analyze the changes of the reading ability for the subjects, KNISE-BAAT type A and B reading test were used. Results : According to the tests taken before and after implementing, the Application of Picture Booking Training Protocol using Electronic Media there was a significant improvement in Reading ability (Understanding words, Completion sentence, Vocabulary selection, Vocabulary arrangement, Understanding short text). However, there was no significant difference in Oral Reading. Conclusion : Application of Picture Booking Training Protocol using Electronic Media may be used as a beneficial measure to improve the reading abilities of children with Borderline Intellectual.

• Journal of Climate Change Research
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• v.1 no.1
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• pp.1-11
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• 2010

This study is analyzed based on the statistical data for the effect of Kyoto Protocol which is adopted on 1997. The first greenhouse gas obligation reduction countries such as OECD (Organization for Economic Cooperation and Development), and the first non-obligated developing countries such as China and India, the increasing rate of carbon dioxide emission displayed -10.2% and 88.1% in 2005 with respect to 1990, respectively. This increasing rate is not only shows statistically significant differences but also shows significant meanings when we consider the global increasing rate of carbon dioxide is 29.1%. Changes in the carbon dioxide emissions are also analyzed based on the time of the adaptation of Kyoto Protocol, time of the publication of the second and third reports of IPCC, and withdrawal of the Kyoto Protocol of the United States. Withdrawal of the Kyoto Protocol of the United States is the most significantly affected to the differences in the carbon dioxide emission rates rather than the adaptation of Kyoto Protocol, international agreement on the greenhouse gas reduction, and belief on the scientific evidence for the reasons for increasing carbon dioxide concentrations. Therefore, acceptance of the post-Kyoto Protocol in the United States is very important in order to success as a climate regime.