• Journal of Multimedia Information System
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• v.4 no.4
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• pp.243-248
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• 2017

In a basic engineering design class, first year engineering department students learn about engineering design relevant theories and carry out simple projects in teams. By doing a group project in this subject, students develop basic skills such as creativity, teamwork, communication, and problem solving. Before, class proceeded in a way where teams were randomly configured in the beginning of semester and students began working on their project immediately. However, this research introduces a new method where at the beginning of the semester, students are assigned group assignments. Teammates are randomly chosen and constantly switched so that students get a chance to work with different people and experience diverse styles and characteristics. Then, they autonomously form into teams with people they work best and carry out their project. We present the behavior of a monkey robot that recognizes emotions as a case of applying the proposed method. The feedback from the students suggest that this proposed team forming method serves to be effective especially since students who were not aware of other students' characteristics can get to know one another better and form a productive team.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2189-2192
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• 1998

The objective of this paper is, based upon the principles of artificial life, to induce emergent behaviors of multiple autonomous mobile robots which form from simple local rules to complex global intelligence. Here, we propose an architecture of neural network learing with reinforcement signals which perceives the neighborhood information and decides the direction and the velocity of movement as mobile robots navigates in a group. As results of the simulations, the optimum weights are obtained in real time, which not only prevent from the collisions between agents and obstacles in the dynamic environment, but also have the mobile robots move and keep in various patterns.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.751-755
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• 2005

We propose a sound source localization method using the Head-Related-Transfer-Function (HRTF) to be implemented in a robot platform. In conventional localization methods, the location of a sound source is estimated from the time delays of wave fronts arriving in each microphone standing in an array formation in free-field. In case of a human head this corresponds to Interaural-Time-Delay (ITD) which is simply the time delay of incoming sound waves between the two ears. Although ITD is an excellent sound cue in stimulating a lateral perception on the horizontal plane, confusion is often raised when tracking the sound location from ITD alone because each sound source and its mirror image about the interaural axis share the same ITD. On the other hand, HRTFs associated with a dummy head microphone system or a robot platform with several microphones contain not only the information regarding proper time delays but also phase and magnitude distortions due to diffraction and scattering by the shading object such as the head and body of the platform. As a result, a set of HRTFs for any given platform provides a substantial amount of information as to the whereabouts of the source once proper analysis can be performed. In this study, we introduce new phase and magnitude criteria to be satisfied by a set of output signals from the microphones in order to find the sound source location in accordance with the HRTF database empirically obtained in an anechoic chamber with the given platform. The suggested method is verified through an experiment in a household environment and compared against the conventional method in performance.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1458-1463
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• 2004

Tracking is one of the most important pre-required task for many application such as human-computer interaction through gesture and face recognition, motion analysis, visual servoing, augment reality, industrial assembly and robot obstacle avoidance. Recently, 3D information of object is required in realtime for many aforementioned applications. 3D tracking is difficult problem to solve because during the image formation process of the camera, explicit 3D information about objects in the scene is lost. Recently, many vision system use stereo camera especially for 3D tracking. The 3D feature based tracking(3DFBT) which is on of the 3D tracking system using stereo vision have many advantage compare to other tracking methods. If we assumed the correspondence problem which is one of the subproblem of 3DFBT is solved, the accuracy of tracking depends on the accuracy of camera calibration. However, The existing calibration method based on accurate camera model so that modelling error and weakness to lens distortion are embedded. Therefore, this thesis proposes 3D feature based tracking method using SVM which is used to solve reconstruction problem.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.454-460
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• 2015

Acoustic emission (AE) is one of the promising methods for detecting the formation of stress corrosion cracks (SCCs) in laboratory tests. This method has the advantage of online inspection. Some studies have been conducted to investigate the characteristics of AE parameters during SCC propagation. However, it is difficult to classify the distinct features of SCC behavior. Because the previous studies were performed on slow strain rate test or compact tension specimens, it is difficult to make certain correlations between AE signals and actual SCC behavior in real tube-type specimens. In this study, the specimen was a AISI 304 stainless steel tube widely applied in the nuclear industry, and an accelerated test was conducted at high temperature and pressure with a corrosive environmental condition. The study result indicated that intense AE signals were mainly detected in the elastic deformation region, and a good correlation was observed between AE activity and crack growth. By contrast, the behavior of accumulated counts was divided into four regions. According to the waveform analysis, a specific waveform pattern was observed during SCC development. It is suggested that AE can be used to detect and monitor SCC initiation and propagation in actual tubes.

• Journal of Fashion Business
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• v.25 no.6
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• pp.119-130
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• 2021

This study investigated the effects of the chatbot's level of anthropomorphism - closeness to the human form - and its self-disclosure - delivery of emotional exchange with the chatbot through its facial expressions and chatting message on the user's intention to accept the service. A 2 (anthropomorphism: High vs. Low) × 2 (self-disclosure through facial expressions: High vs. Low) × 2 (self-disclosure through conversation: High vs. Low) between-subject factorial design was employed for this study. An online survey was conducted and a total of 234 questionnaires were used in the analysis. The results showed that consumers used chatbot service more when emotions were disclosed through facial expressions, than when it disclosed fewer facial expressions. There was statistically significant interaction effect, indicating the relationship between chatbot's self-disclosure through facial expression and the consumers' intention to use chatbot service differs depending on the extent of anthropomorphism. In the case of "robot chatbots" with low anthropomorphism levels, there was no difference in intention to use chatbot service depending on the level of self-disclosure through facial expression. When the "human-like chatbot" with high anthropomorphism levels discloses itself more through facial expressions, consumer's intention to use the chatbot service increased much more than when the human-like chatbot disclosed fewer facial expressions. The findings suggest that chatbots' self-disclosure plays an important role in the formation of consumer perception.

• Journal of the Korean Geotechnical Society
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• v.28 no.10
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• pp.69-77
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• 2012

Clogging of drainage pipes by scale is an important problem in civil engineering works. Although scale deposits can be removed by acid treatment or water jetting, these treatments are costly and have many disadvantages. In this study, scale samples from tunnel drainage pipes were analyzed using SEM-EDS and XRD. The main ingredient in scale was $CaCO_3$ of the calcite crystal form. Drainage experiments and recirculation type experiments were conducted to control and remove scale deposits, which were determined through visual and weight measuring analysis. As a result, Quantum Stick has the effect of limiting formation of scale.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.139-145
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• 2006

Feature extraction technique in digital images has many applications such as robot vision, medical diagnostic system, and motion video transmission, etc. There are several methods for extracting features in digital images for example nonlinear gradient, nonlinear laplacian, and entropy convolutional filter. However, conventional convolutional filters are usually not efficient to extract features in an image because image feature formation in eyes is more sensitive to dark regions than to bright regions. A few nonlinear filters using difference between arithmetic mean and harmonic mean in a window for extracting sketch features are described in this paper They have some advantages, for example simple computation, dependence on local intensities and less sensitive to small intensity changes in very dark regions. Experimental results demonstrate more successful features extraction than other conventional filters over a wide variety of intensity variations.

• Journal of Gastric Cancer
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• v.16 no.2
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• pp.63-71
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• 2016

Pylorus-preserving gastrectomy (PPG) is a function-preserving surgery for the treatment of early gastric cancer (EGC), aiming to decrease the complication rate and improve postoperative quality of life. According to the Japanese gastric cancer treatment guidelines, PPG can be performed for cT1N0M0 gastric cancer located in the middle-third of the stomach, at least 4.0 cm away from the pylorus. Although the length of the antral cuff gradually increased, from 1.5 cm during the initial use of the procedure to 3.0 cm currently, its optimal length still remains unclear. Standard procedures for the preservation of pyloric function, infra-pyloric vessels, and hepatic branch of the vagus nerve, make PPG technically more difficult and raise concerns about incomplete lymph node dissection. The short- and long-term oncological and survival outcomes of PPG were comparable to those for distal gastrectomy, but with several advantages such as a lower incidence of dumping syndrome, bile reflux, and gallstone formation, and improved nutritional status. Gastric stasis, a typical complication of PPG, can be effectively treated by balloon dilatation and stent insertion. Robot-assisted pylorus-preserving gastrectomy is feasible for EGC in the middle-third of the stomach in terms of the short-term clinical outcome. However, any benefits over laparoscopy-assisted PPG (LAPPG) from the patient's perspective have not yet been proven. An ongoing Korean multicenter randomized controlled trial (KLASS-04), which compares LAPPG and laparoscopy-assisted distal gastrectomy for EGC in the middle-third of the stomach, may provide more clear evidence about the advantages and oncologic safety of PPG.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.161-167
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• 2019

In this paper, the performance verification of an around-view sonar and an excavation depth measuring sonar applicable to track-based ROVs (Remotely Operated underwater Vehicles) for heavy duty work is studied. For the performance verification, an experiment is carried out in a water tank and at sea by attaching the around-view sonar and the excavation depth measuring sonar for a heavy work ROV. In the case of the around-view sonar, image sonars are mounted on ROV in four directions (front, back, left and right) and in the case of the excavation depth measuring sonar, the same kind of MBES (Multi Beam Echo Sounder) is mounted on the front of the ROV. The result of an operation test of the ROV equipped with these sonars shows that the sonar systems are rarely affected by high turbidity due to sedimentation during the operation. In the case of the around-view sonar, it is possible to see rock formation, gravel and sandbank 30 m ahead of the ROV. It is confirmed that the excavation depth can be measured after the ROV has performed the excavation. This experiment demonstrates that the ROV can improve the efficiency of the work by utilizing the around-view sonar and the excavation depth measuring sonar.