• Proceedings of the PSK Conference
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• 2003.10b
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• pp.183.1-183.1
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• 2003

The synthesis of various cyclic carbamate compounds and amino alcohols has attracted attention in the past because of their potential as antibiotics, antitumor, analgenics, anticonvulsants. Several methods for the preparation of cyclic carbamate compounds have previously been reported including the use of heterocumulenes. We have recently described the novel synthetic method for N-protected amines from various ethers using Chlorosulfonyl isocyanate(CSI) and found that the mechanism of our CSI reaction is a competitive reaction of $S_N1$ and $S_ Ni$ mechanisms according to the stability of carbocation intermediates. (omitted)

• American Studies
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• v.43 no.1
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• pp.115-143
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• 2020

The U.S. Congress has been known to effectively control the bureaucracy. On one hand, Congress adjusts the degree of discretion provided to the bureaucracy when making agencies or legislation: ex ante control. On the other hand, it also performs the oversight activities to punish or correct undesirable behaviors of bureaucrats: ex post control. While the dynamics of each control mechanism is widely examined theoretically, few have attempted to empirically investigate this with a special attention to partisan politics in Congress. I attempt to fill this gap by measuring the two types of control mechanisms, testing theoretical assertions, and analyzing the dynamics under the two control mechanisms.

• Korean Journal of Cognitive Science
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• v.16 no.3
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• pp.155-174
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• 2005

Oh and Kim (2004) and Woodman and Lurk (2004) demonstrated that spatial working memory (SWM) load Interfered concurrent visual search and that search process also impaired the maintenance of spatial information implying that visual search and SWM task both require access to the same limited-capacity mechanism. Two obvious possibilities have been suggested about what this shared limited-capacity mechanism is: common demand for attention to the locations where the items f9r the two tasks were presented (spatial attention load hypothesis), and common use of working memory to maintain a record of locations have been processed(SWM load hypothesis). To test these two hypothetical explanations, Experiment 1 replicated the mutual interference between visual search and SWM task in spite of difference of procedure with preceding researches; possible areas where the items for two tasks were presented were not separated. In Experiment 2, we presented the items for visual search either in the same quadrants where the items for SWM task had appeared (same-location rendition) or in the different quadrants (different-location condition). As a result, search efficiency was more impaired in the different-location condition than in the same-location condition. The memory accuracy was worse in the different-location rendition than in the same-location rendition. Overall results of study indicate that the mutual interference between SWM and visual search might be related to the overload of spatial attention, but not to that of SWM.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.1-12
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• 2020

In the medical field, numerical imbalance of data due to differences in disease prevalence is a common problem. It reduces the performance of a artificial intelligence network, leading to difficulties in learning a network with good performance. Recently, generative adversarial network (GAN) technology has been introduced as a way to address this problem, and its ability has been demonstrated by successful applications in various fields. However, it is still difficult to achieve good results in solving problems with performance degraded by numerical imbalances because the image resolution of the previous studies is not yet good enough and the structure in the image is modeled locally. In this paper, we propose a multi-scale conditional generative adversarial network based on attention mechanism, which can produce high resolution images to solve the numerical imbalance problem of chest X-ray image data. The network was able to produce images for various diseases by controlling condition variables with only one network. It's efficient and effective in that the network don't need to be learned independently for all disease classes and solves the problem of long distance dependency in image generation with self-attention mechanism.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.2
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• pp.259-266
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• 2009

An experimental study was conducted to investigate the effects of forcing amplitude on the flow structure near the nozzle exit of forced jet diffusion flames. The jet was excited up to the blowout occurrence by a considerable large amplitude with a periodic velocity fluctuation at the tube resonating frequency. In the attached flame regime, we disclosed the very interesting result newly that adding of a moderate forcing amplitude caused the jet flame to become longer in spite of being forced. Particular attention is focused on the turnabout mechanism of vortex roll-up around the elongated flame, which has not been reported previously, and on the inner coherent structure of the forced jet in the attached flame regime. From the velocity and flow visualization results, it was ascertained that the surrounding air due to the occurrence of negative velocity parts was suck into the fuel nozzle. To aid in understanding the rotating phenomenon of coherent structure, we present a schematic diagram of the turnabout mechanism of vortex roll-up. The mechanism of vortex turnabout phenomenon can be easily understood by considering the positive and negative velocity amplitudes about the instantaneous velocity of the forcing flow, as shown in this diagram.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.786-799
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• 2018

Recently, NFV has attracted attention as a next-generation network virtualization technology for hardware -independent and efficient utilization of resources. NFV is a technology that not only virtualize computing, server, storage, network resources based on cloud computing but also connect Multi-Tenant of VNFs, a software network function. Therefore, it is possible to reduce the cost for constructing a physical network and to construct a logical network quickly by using NFV. However, in NFV, when a new VNF is added to a running Tenant, authentication between VNFs is not performed. Because of this problem, it is impossible to identify the presence of Fake-VNF in the tenant. Such a problem can cause an access from malicious attacker to one of VNFs in tenant as well as other VNFs in the tenant, disabling the NFV environment. In this paper, we propose Auto-configurable Security Mechanism in NFV including authentication between tenant-internal VNFs, and enforcement mechanism of security policy for traffic control between VNFs. This proposal not only authenticate identification of VNF when the VNF is registered, but also apply the security policy automatically to prevent malicious behavior in the tenant. Therefore, we can establish an independent communication channel for VNFs and guarantee a secure NFV environment.

• Journal of Pharmaceutical Investigation
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• v.22 no.2
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• pp.77-96
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• 1992

In recent years intranasal administration of drugs has received great attention as a convenient and efficent method of drug delivery because of its potential to improve the systemic effect of substances with a poor oral bioavailability. In addition to offering advantages such as rapid absorption, fast onset of action and avoiding the first -pass effect, it provides for delivery of drugs from very lipophilic drugs such as steroids to polar and hydrophilic drugs such as peptides and proteins. However, little is still known about the nature of various barriers existing in the nasal mucosae as well as mechanism by which these molecules are absorbed. This review article therefore intends to discuss nasal physiology, experimental methods and evaluation of absorption from the nasal cavity, factors influencing nasal absorption, mechanism of nasal absorption, approaches to improve the residence time and to obtain the sustained-release effect of intranasally administered drugs, promoters and mechanism for the enhancement of nasal absorption, Several examples for intranasal delivery of various systemically effective drugs will be reviewed and illustrated. Drug metabolism in the nasal mucosae and problems associated with intranasal administration of drugs will be also discussed.

• Journal of Information Technology Services
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• v.5 no.2
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• pp.93-105
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• 2006

More emphasis has recently been put on the strategic application of IT, the linkage and integration between information system, and business process for value increase of a company's business. Thus, it is high time to redefine the concept of IT governance in order to effectively manage various IT services and assets. However, less attention has been paid to the practical study of domestic firms, compared to in the academic and industrial level. In this study, the current situation of IT governance setup and various factors for future development will be examined by a case study to explore activities, types, and determinants of decision making process that companies are currently conducting regarding IT governance. For the purpose of comparative analysis, two large enterprises were chosen with similar size of sales and high investment rate for IT within the same industry, and in-depth analysis was conducted based on the interviews of the concerned parties and in-house materials, from the perspective of structure, process, and relational mechanism. By the case study on IT governance of company 'A' and 'B', decision making mechanism and factors will be analyzed, which will indicate detailed characteristics of each decision-making field and its components for general application. By doing so, it is expected to be used as reference in building IT governance that fits the environment of a firm in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.421-429
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• 2006

Recently, DHT-based Structured P2P System have a attention to scalability and providing efficient lookup by routing. Retrieving content of DHT-based P2P require knowledge of the exact identifier of sharing file. But user may wish to search for sharing file using descriptive keyword or content. To resolve the problem, this paper propose Extended-CAN mechanism to support keyword search. We defined content-based keyword and identifier of sharing file, and PLS extended to KID and CKD for keyword, common keyword processing. As a result, Extended-CAN mechanism provide efficient keyword search for DHT-based Structured P2P System.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1611-1629
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• 2016

Recently, deploying WiFi access points (APs) for facilitating indoor localization has attracted increasing attention. However, most existing mechanisms in this aspect are typically simulation based and further they did not consider how to jointly utilize pre-existing APs in target environment and newly deployed APs for achieving high localization performance. In this paper, we propose a measurement-based AP deployment mechanism (MAPD) for placing APs in target indoor environment for assisting fingerprint based indoor localization. In the mechanism design, MAPD takes full consideration of pre-existing APs to assist the selection of good candidate positions for deploying new APs. For this purpose, we first choose a number of candidate positions with low location accuracy on a radio map calibrated using the pre-existing APs and then use over-deployment and on-site measurement to determine the actual positions for AP deployment. MAPD uses minimal mean location error and progressive greedy search for actual AP position selection. Experimental results demonstrate that MAPD can largely reduce the localization error as compared with existing work.