• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1142-1147
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• 2016

Recently, IoT(Internet of Things) has been extensively researching to provide intelligent services by fusing ICT. Especially with the advent of Germany's Industry 4.0, it is emphasized the importance of the industrial IoT to maximize the production capacity. Accordingly, a lot of efforts to spread the smart factory base of industrial IoT have continued domestically as well as abroad. But the current smart factory systems have controlled equipment using the data declared in the embedded systems. Therefore, it is difficult to control environment that lots of equipment is installed. In this paper, we proposed equipment control system based on data base access method for industrial IoT. This method controls the equipment using data base from parameter of equipment. Through experiments that the system apply to mold shot system with a number of variables, it is shown that the proposed method can efficiently control a number of devices.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.661-666
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• 2016

The Internet of Things (IoT) is an infrastructure of physical objects that could be connected to the Internet. Most of these are low performance to ensure a reasonable cost for the smart physical objects. Thus, these devices usually use a lightweight messaging protocol: message queue telemetry transport with SSL/TLS. Cipher suites in device are fixed by default and selected based on preference in SSL/TLS. However, the selected cipher suite provides high security level more than expected. This limitation causes energy waste and overhead of devices. In order to counter this problem, we proposed fuzzy logic based cipher suite decision method to improve energy efficiency. Our proposed method saved 36.03% energy.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.9
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• pp.263-272
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• 2023

Industrial Internet of Things (IIoT) is an important factor in increasing production efficiency in industrial sectors, along with data collection, exchange and analysis through large-scale connectivity. However, as traffic increases explosively due to the recent spread of IIoT, an allocation method that can efficiently process traffic is required. In this thesis, I propose a two-stage task offloading decision method to increase successful task throughput in an IIoT environment. In addition, I consider a hybrid offloading system that can offload compute-intensive tasks to a mobile edge computing server via a cellular link or to a nearby IIoT device via a Device to Device (D2D) link. The first stage is to design an incentive mechanism to prevent devices participating in task offloading from acting selfishly and giving difficulties in improving task throughput. Among the mechanism design, McAfee's mechanism is used to control the selfish behavior of the devices that process the task and to increase the overall system throughput. After that, in stage 2, I propose a multi-armed bandit (MAB)-based task offloading decision method in a non-stationary environment by considering the irregular movement of the IIoT device. Experimental results show that the proposed method can obtain better performance in terms of overall system throughput, communication failure rate and regret compared to other existing methods.

• ETRI Journal
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• v.39 no.5
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• pp.662-671
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• 2017

Coronary artery disease (CAD) is a major cause of death in the world. As a non-invasive imaging modality, computed tomography angiography (CTA) is now usually used in clinical practice for CAD diagnosis. Precise quantification of coronary stenosis is of great interest for diagnosis and treatment planning. In this paper, a novel cluster method based on a Modified Student's t-Mixture Model is applied to separate the region of vessel lumen from other tissues. Then, the area of the vessel lumen in each slice is computed and the estimated value of it is fitted with a curve. Finally, the location and the level of the most stenoses are captured by comparing the calculated and fitted areas of the vessel. The proposed method has been applied to 17 clinical CTA datasets and the results have been compared with reference standard degrees of stenosis defined by an expert. The results of the experiment indicate that the proposed method can accurately quantify the stenosis of the coronary artery in CTA.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.179-185
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• 2019

A core technology of social robot is voice recognition and dialogue engine technology, but too much money is needed for development and an implementation of robot's conversation function is difficult resulting from insufficiency of performance. Dialogue function's implementation between human and robot can be possible due to advance of cloud AI technology and several company's supply of their open API. In this paper, current intelligent social robot technology trend is investigated and effective social robot system architecture is designed. Also an effective analysis and design method of social robot system will be presented by showing user requirement analysis using object-oriented method, flowchart and screen design.

• Earthquakes and Structures
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• v.16 no.3
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• pp.359-368
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• 2019

This paper focuses on the study of dynamic analysis of thick plates resting on Winkler foundation. The governing equation is derived from Mindlin's theory. This study is a parametric analysis of the reflections of the thickness / span ratio, the aspect ratio and the boundary conditions on the earthquake excitations are studied. In the analysis, finite element method is used for spatial integration and the Newmark-${\beta}$ method is used for the time integration. While using finite element method, a new element is used. This element is 17-noded and it's formulation is derived from using higher order displacement shape functions. C++ program is used for the analyses. Graphs are presented to help engineers in the design of thick plates subjected to earthquake excitations. It is concluded that the 17-noded finite element is used in the earthquake analysis of thick plates. It is shown that the changes in the aspect ratio are more effective than the changes in the aspect ratio. The center displacements of the reinforced concrete thick clamped plates for b/a=1, and t/a=0.2, and for b/a=2, and t/a=0.2, reached their absolute maximum values of 0.00244 mm at 3.48 s, and of 0.00444 mm at 3.48 s, respectively.

• The KIPS Transactions:PartB
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• v.17B no.5
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• pp.363-374
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• 2010

In this paper, we propose the method for extracting Homogeneity Threshold($H_T$) and for segmenting homogeneous regions by USRG(Unseeded Region Growing) with $H_T$. The $H_T$ is a criterion to distinguish homogeneity in neighbor pixels and is computed automatically from the original image by proposed method. Theoretical background for proposed method is based on the Otsu's single level threshold method. The method is used to divide a small local part of original image int o two classes and the sum($\sigma_c$) of standard deviations for the classes to satisfy special conditions for distinguishing as different regions from each other is used to compute $H_T$. To find validity for proposed method, we compare the original image with the image that is regenerated with only the segmented homogeneous regions and show up the fact that the difference between two images is not exist visually and also present the steps to regenerate the image in order the size of segmented homogeneous regions and in order the intensity that includes pixels. Also, we show up the validity of proposed method with various results that is segmented using the homogeneity thresholds($H^*_T$) that is added a coefficient ${\alpha}$ for adjusting scope of $H_T$. We expect that the proposed method can be applied in various fields such as visualization and animation of natural image, anatomy and biology and so on.

• Journal of Korean Society for Quality Management
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• v.41 no.3
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• pp.457-463
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• 2013

Purpose: For effective quality assurance activities, BOM-based quality assurance method is presented. This study introduces various BOM conversions such as Q-BOM, T-BOM, and S-BOM based on M-BOM structure. Methods: Product quality control via Q-BOM manages inspection/audit information, overall supply-chain of product, part requirements, and inventory status. T-BOM manages part traceability, and S-BOM enables statistical control over key process and parts at various hierarchy levels. Results: Quality plan template was developed based on the study results of BOM system including Q-BOM, T-BOM, and S-BOM. Conclusion: Through BOM(Q-BOM, T-BOM, and S-BOM) study and development of quality plan template, more systematic and comprehensive quality management plan is achieved.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.249-252
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• 2002

we have studied the characteristics of PHEMT's with gate recess etching method. The DC characterization of PHTMT fabricated with the wide single recess methods is a maximum drain current density of 319.4 ㎃/mm and a peak transconductance of 336.7 ㎳/mm. The RF measurements were obtained in the frequency range of 1~50GHz. At 50GHz, 3.69dB of 521 gain were obtained and a current gain cut-off frequency(f$_{T}$) of 113 CH and a maximum frequency of oscillation(f$_{max}$) of 172 Ghz were achieved from this device. On the other hand, a maximum drain current of 367 mA/mm, a peak transconduclancc of 504.6 mS/mm, S$_{21}$ gain of 2.94 dB, a current gain cut-off frequency(f$_{T}$) of 101 CH and a maximum frequency of oscillation(f$_{max}$) of 113 fa were achieved from the PHEMT's fabricated by the .narrow single recess methods.methods.

• Journal of the Korea Furniture Society
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• v.24 no.3
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• pp.293-301
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• 2013

Through 1960 and 1970s, there had been constant endeavor in order to succeed the korean traditional architectural heritages. Among those efforts Ahn Yung Bae's book "Exterior Space in Traditional Korean Architecture"presented unique methodology utilizing abstraction of space and movement of subject. His method doesn't refer traditional form of architecture. He ignores formal elements. Instead, he reads space through subject's movement and this reading act creates meaning of space. So, he constructed knowledge not about the object of traditional architecture but the subject of today. Ahn's book opens new discourse based on traditional korean architecture. His analyses didn't deal with the form of traditional space, but the experiences of observer. However many historical documents related to architecture had not been interpreted until nineties and the succession of heritage became to be broken by modernity through 20th century. In this situation his book showed the unavoidable method, that is, the modernization of tradition.