• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.899-910
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• 2016

Asymptotic tests are often not suitable for the analysis of sparse ordered contingency tables as asymptotic p-values may either overestimate or underestimate the true pvalues. In this pater, we describe permutation procedures in which we compute exact or resampling p-values for a weighted specific-category agreement in ordered $k{\times}k$ contingency tables. We use the weighted specific-category kappa proposed by $Kv{\dot{a}}lseth$ to measure the extent to which two independent raters agree on the specific categories. We carried out comparison studies between exact p-values, resampling p-values and asymptotic p-values using $3{\times}3$ contingency data (real and artificial data sets) and $4{\times}4$ artificial contingency data.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.595-598
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• 2007

Vast amount of XML documents raise interests in how they will be used and how far their usage can be expanded. This paper has two central goals: 1) easy and fast retrieval of XML documents or relevant elements; and 2) efficient and stable management of large-size XML documents. The keys to develop such a practical system are how to segment a large XML document to smaller fragments and how to store them. In order to achieve these goals, we designed SCOF(Service-centric Object Fragmentation) model, which is a semi-decomposition method based on conversion rules provided by XML database managers. Keyword-based search using SCOF model then retrieves the specific elements or attributes of XML documents, just as typical XML query language does. Even though this approach needs the wisdom of managers in XML document collection, SCOF model makes it efficient both retrieval and management of massive XML documents.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.3
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• pp.183-188
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• 1997

A method for designing a broadband transducer was investigated experimentally. Control of the resonance frequency of a Piezoelectric circular transducer with two pairs of electrodes was achieved by varying the inductance of external coil connected across the terminal of one pair of electrodes of transducer. The conductance curves of transducer in water were obtained as a function of the inductance value in mH of the coil used in the tuning. As the tuning inductance is increased in value, the resonance frequency is reduced toward the fundamental frequency of 50 kHz. This interesting result suggest that it is possible to produce a continuously tunable transducer covering a frequency range between 61.3 kHz and 121.7 kHz by varying the inductance value of external coil from 2.7 mH to 15.0 mH. One of other problems in the design and construction of such broadband transducer is the transducer efficiency, but this will be the subject of our future work.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1498-1508
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• 2011

A cloud service customer has no other way but to wait for his lost data to be recovered by the cloud service provider when the data was lost or not accessible for a while due to the provider's system failure, cracking attempt, malfunction, or outage. We consider a solution to address this problem that can be implemented in the cloud client's domain, rather than in the cloud service provider's domain. We propose a high level architecture and scheme for successfully retrieving data units even when several cloud storages are not accessible at the same time. The scheme is based on a clever way of partitioning and partial overlapping of data for being stored on multiple cloud storages. In addition to providing a high level of data availability, the scheme makes it possible to re-encrypt data units with new keys in a user transparent way, and can produce the complete log of every user's data units accessed, for assessing data disclosure, if needed.

• The KIPS Transactions:PartB
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• v.18B no.2
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• pp.57-66
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• 2011

To prevent cardiac diseases, quantifying cardiac function is important in routine clinical practice by analyzing blood volume and ejection fraction. These works have been manually performed and hence it requires computational costs and varies depending on the operator. In this paper, an automatic left ventricle segmentation algorithm is presented to segment left ventricle on cardiac magnetic resonance images. After coil sensitivity of MRI images is compensated, a K-mean clustering scheme is applied to segment blood area. A graph searching scheme is employed to correct the segmentation error from coil distortions and noises. Using cardiac MRI images from 38 subjects, the presented algorithm is performed to calculate blood volume and ejection fraction and compared with those of manual contouring by experts and GE MASS software. Based on the results, the presented algorithm achieves the average accuracy of 6.2mL${\pm}$5.6, 2.9mL${\pm}$3.0 and 2.1%${\pm}$1.5 in diastolic phase, systolic phase and ejection fraction, respectively. Moreover, the presented algorithm minimizes user intervention rates which was critical to automatize algorithms in previous researches.

• The Transactions of the Korea Information Processing Society
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• v.5 no.9
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• pp.2302-2311
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• 1998

The problem of scheduling general packet traffic on WDM optical interconnection networks is NP-complete, It is known that the list scheduling is a good approximation algurithm fur this problem, The resulting list schedules vary depending on the order of transmitters considered to be placed on each time slot We propose an improvement of the list scheduling that tries different orders of transmitters to obtain shorter schedule lengths, Genetic algorithms are used to explore various orders of transmitters.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1259-1265
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• 2004

In many applications, producing labeled data is costly and time consuming while an enormous amount of unlabeled data is available with little cost. Therefore, it is natural to ask whether we can take advantage of these unlabeled data in classification teaming. In machine learning literature, the co-training method has been widely used for this purpose. However, the current co-training method requires the entire features to be split into two independent sets. Therefore, in this paper, we improved the current co-training method in a number of ways, and proposed a new co-training method which do not need the feature split. Experimental results show that our proposed method can significantly improve the performance of the current co-training algorithm.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.2
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• pp.43-54
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• 1997

In this paper, we introduce a secure and minimal protocol for authenticated key distribution over the CDMA mobile communication network. The CDMA mobile communication network has been developed the security protocol that provides a means for user authentication and subsequent protection of user traffic. However, this model has no security assumptions for the intermediate, fixed networks. To avoiding these drawbacks, we introduce a minimal authenticated key distribution protocol. This protocol provides the security of the intermediate and fixed network in mobile environment, and maintains the confidentiality of user identification and the minimum size of information flow compared with the existing protocols.

• Journal of the Korean Geographical Society
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• v.30 no.4
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• pp.389-410
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• 1995

Large metropolitan areas in the US are distinguished by highly fragmented fiscally independent suburban municipalities and special districts. The suburban fragmentation implies the congregation of similar socio-economic groups escaped from central cities and the disparity of geographical resources among local government jurisdictions. This study examines St.Louis County suburbs as a case study for the implictions of suburban governmental fragmentation and the fiscal disparities across local governmental boundaries by analyzing their relationship with public service provision using police and public school services as examples. The distribution of fiscal resources across political boundaries, the processes which created them, and public service inequalities reproduced from the disparity of fiscal resources reveal the causes and consequences of suburban governmental fragmentation. The central part of suburban fragmentation is the segregation of public goods consumption reproduced from the disparity of local fiscal resources, and it acts as a basic geographical segregating force in the suburban spatial organization.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.267-273
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• 2011

In this paper, we proposed the method to detect brain tumor region in MR images. Our method is composed of 3 parts, detection of tumor slice, detection of tumor region and tumor boundary detection. In the tumor slice detection step, a slice which contains tumor regions is distinguished using symmetric analysis in 3D brain volume. The tumor region detection step is the process to segment the tumor region in the slice distinguished as a tumor slice. And tumor region is finally detected, using spatial feature and symmetric analysis based on the cluster information. The process for detecting tumor slice and tumor region have advantages which are robust for noise and requires less computational time, using the knowledge of the brain tumor and cluster-based on symmetric analysis. And we use the level set method with fast marching algorithm to detect the tumor boundary. It is performed to find the tumor boundary for all other slices using the initial seeds derived from the previous or later slice until the tumor region is vanished. It requires less computational time because every procedure is not performed for all slices.