• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.857-864
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• 2020

The multi-functional VoIP phone supports the Ethernet protocol in the TIPS(: Tactical IP Switch), which is one of the sub-systems of the tactical information and communication system (TICN). It provides secured voice / video calls in conjunction with VoIP exchanges and supports differential services such as multi-party calls and command functions. In this paper, improving methods have been proposed to reduce power supply defects in the field of multi-functional VoIP phones. The power supply part was improved by applying TVS of the output voltage inlet of the dedicated adapter of the multi-functional VoIP phone, TVS of the PoE module input, adding blocking diodes, and adding DC / DC converters behind the poly-switch. Also, functional and environmental tests were performed to verify the validity of the proposed methods.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.53-69
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• 2011

Vision and voice-based technologies are commonly utilized for human-robot interaction. But it is widely recognized that the performance of vision and voice-based interaction systems is deteriorated by a large margin in the real-world situations due to environmental and user variances. Human users need to be very cooperative to get reasonable performance, which significantly limits the usability of the vision and voice-based human-robot interaction technologies. As a result, touch screens are still the major medium of human-robot interaction for the real-world applications. To empower the usability of robots for various services, alternative interaction technologies should be developed to complement the problems of vision and voice-based technologies. In this paper, we propose the use of accelerometer-based gesture interface as one of the alternative technologies, because accelerometers are effective in detecting the movements of human body, while their performance is not limited by environmental contexts such as lighting conditions or camera's field-of-view. Moreover, accelerometers are widely available nowadays in many mobile devices. We tackle the problem of classifying acceleration signal patterns of 26 English alphabets, which is one of the essential repertoires for the realization of education services based on robots. Recognizing 26 English handwriting patterns based on accelerometers is a very difficult task to take over because of its large scale of pattern classes and the complexity of each pattern. The most difficult problem that has been undertaken which is similar to our problem was recognizing acceleration signal patterns of 10 handwritten digits. Most previous studies dealt with pattern sets of 8~10 simple and easily distinguishable gestures that are useful for controlling home appliances, computer applications, robots etc. Good features are essential for the success of pattern recognition. To promote the discriminative power upon complex English alphabet patterns, we extracted 'motion trajectories' out of input acceleration signal and used them as the main feature. Investigative experiments showed that classifiers based on trajectory performed 3%~5% better than those with raw features e.g. acceleration signal itself or statistical figures. To minimize the distortion of trajectories, we applied a simple but effective set of smoothing filters and band-pass filters. It is well known that acceleration patterns for the same gesture is very different among different performers. To tackle the problem, online incremental learning is applied for our system to make it adaptive to the users' distinctive motion properties. Our system is based on instance-based learning (IBL) where each training sample is memorized as a reference pattern. Brute-force incremental learning in IBL continuously accumulates reference patterns, which is a problem because it not only slows down the classification but also downgrades the recall performance. Regarding the latter phenomenon, we observed a tendency that as the number of reference patterns grows, some reference patterns contribute more to the false positive classification. Thus, we devised an algorithm for optimizing the reference pattern set based on the positive and negative contribution of each reference pattern. The algorithm is performed periodically to remove reference patterns that have a very low positive contribution or a high negative contribution. Experiments were performed on 6500 gesture patterns collected from 50 adults of 30~50 years old. Each alphabet was performed 5 times per participant using $Nintendo{(R)}$ $Wii^{TM}$ remote. Acceleration signal was sampled in 100hz on 3 axes. Mean recall rate for all the alphabets was 95.48%. Some alphabets recorded very low recall rate and exhibited very high pairwise confusion rate. Major confusion pairs are D(88%) and P(74%), I(81%) and U(75%), N(88%) and W(100%). Though W was recalled perfectly, it contributed much to the false positive classification of N. By comparison with major previous results from VTT (96% for 8 control gestures), CMU (97% for 10 control gestures) and Samsung Electronics(97% for 10 digits and a control gesture), we could find that the performance of our system is superior regarding the number of pattern classes and the complexity of patterns. Using our gesture interaction system, we conducted 2 case studies of robot-based edutainment services. The services were implemented on various robot platforms and mobile devices including $iPhone^{TM}$. The participating children exhibited improved concentration and active reaction on the service with our gesture interface. To prove the effectiveness of our gesture interface, a test was taken by the children after experiencing an English teaching service. The test result showed that those who played with the gesture interface-based robot content marked 10% better score than those with conventional teaching. We conclude that the accelerometer-based gesture interface is a promising technology for flourishing real-world robot-based services and content by complementing the limits of today's conventional interfaces e.g. touch screen, vision and voice.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.372-375
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• 2008

Drivers need to process dynamic stimulus in real - time with full attention from Telematics environment. However, as the information technology revolution brings more and more data into vehicles, all of it competing for the drivers' attention, the development of automated assistance for driver information processing becomes increasingly import ant. There for e, drivers' workload is very essential factor for safety driving in Telematics environment. In this paper, we have discussed driver distraction caused by driver conversation while driving and proposed voice activity detection algorithm for measuring driver workload. Finally, we show how voice activity detection system works for measuring driver workload.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.4
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• pp.671-688
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• 2018

This study investigates the characteristics of VR stores that emerged as new fashion communication media. Two case studies on Hyundai and eBay VR Department stores were conducted along with a discussion of the function and meaning of the fashion VR store. The results showed that both stores provide novel shopping experiences; however, the two were differentiated in terms of production method and technology implementation level. Functional aspects such as providing shopping efficiency and purchasing service was insufficient in both stores. Instead, they were complementing by means of product rotation, recommendation system, voice guidance, or linkage with an online shopping mall. In experiential aspects, both stores provided a strong sense of immersion. Hyundai VR store enhanced immersion with a high resolution image of a real offline store; however, it lacked in the ability to provide multisensory stimulation such as kinetic sense or auditory stimulation. The eBay VR Department store intensified the immersion experience by providing auditory stimulation as well as visual stimulation that enhanced the speed and distance sense through the utilization of animation. However, the extent of experience was limited in terms of agency and transformation because of the low interactivity found in both store systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.3
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• pp.635-642
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• 2000

We have been derived theoretically the SER's and CLP's of Wireless ATM (WATM) cells employing an OFDM/16QAM modulation scheme in wireless channel modeled as a frequency selective Rayleigh fading channel. The amount of the performance improvement of WATM- OFDM/16QAM systems adopting various coding techniques has been evaluated. In frequency selective Rayleigh fading channel, considering CLP : $10^{-3}$ as a criterion, it is observed that the performance improvement of about 14 dB is obtained in terms of $E_b/N_o$ by employing an OFDM scheme. It is also confirmed that convolutional coding technique gives better performance than the other coding techniques. Especially, when the convolutional codes are adopted to WATM-OFDM/16QAM systems, voice transmission services are sufficiently available with 5 dB of $E_b/N_o$.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.1
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• pp.1-11
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• 2015

A concept of Deep Level Situation Understanding is proposed to realize human-like natural communication (called casual communication) among multi-agent (e.g., humans and robots/machines), where the deep level situation understanding consists of surface level understanding (such as gesture/posture understanding, facial expression understanding, speech/voice understanding), emotion understanding, intention understanding, and atmosphere understanding by applying customized knowledge of each agent and by taking considerations of thoughtfulness. The proposal aims to reduce burden of humans in humans-robots interaction, so as to realize harmonious communication by excluding unnecessary troubles or misunderstandings among agents, and finally helps to create a peaceful, happy, and prosperous humans-robots society. A simulated experiment is carried out to validate the deep level situation understanding system on a scenario where meeting-room reservation is done between a human employee and a secretary-robot. The proposed deep level situation understanding system aims to be applied in service robot systems for smoothing the communication and avoiding misunderstanding among agents.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.373-379
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• 2019

AeroMACS spectrum is a national resource internationally allocated by ITU at WRC-07. AeroMACS is an airport broadband mobile communication infrastructure based on WiMAX-based IEEE 802.16e that enables real-time video, graphics, voice, and high-speed data transmission. With the approval of ICAO's development technology standards in 2008, 50 airports in 11 countries have already completed the testing of D-TAXI or A-SMGCS technology using the AeroMACS infrastructure in 2019, starting in the United States in 2009. With many advantages in safety and convenience in terrestrial telecommunications operations, the system is becoming an area of performance improvement for airport operations in accordance with ICAO's ASBU plan. This paper examines the current status of domestic development of AeroMACS and lists service areas applicable to airlines and operators. It also seeks to promote safe and efficient next-generation airport mobile communication system services by presenting feasible partners management in the mobile area and use of aircraft communication systems for active technology development.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.17 no.2
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• pp.115-126
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• 2006

Background and Objectives : Training of breath support and laryngeal muscles control are important components in the development of the singing voice. The purpose of this study is to compare characteristics of respiratory and phonatory control on pitch, loudness, register change with untrained males and trained male singers. Materials and Methods : The 11 untrained males and 11 trained male singers participated. Closed Quotient(CQ), fundamental frequency (fo) and relative volume contribution of the rib cage (in percentage rib cage, % RC) and relative volume contribution of abdomen (in percentage abdomen, % AB) were measured during various pitch, loudness, register tasks using /a/ vowel phonation : Legato, staccato with C3-D3-E3-F3-G3 notes and crescendo and decrescendo with C3 note as well as modal register with C3 and falsetto register with C4 note using an integrated analysis system of Respiration, EGG and Voice. Results : (1) When pitch increased with legato task, loudness also increased in untrained male group but maintained in trained male singers. CQ was also increased both untrained and trained male singers but it was not significantly different ($p>.05$). The abdomen contribution to lung volume were significantly predominant both in inhalation and exhalation in trained males singers ($p<.05$). (2) When pitch increased with staccato task, CQ was not significantly different in untrained but significantly different in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$) (3) When loudness increased with crescendo, fo was significantly increased with increasing CQ in untrained males but fo was relatively consistent with increasing CQ in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). (4) Most male singers were able to change register from modal to falsetto register, but untrained males were not. Thus, CQ was significantly different between modal and falsetto register in trained male singers ($p<.05$). The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). Conclusion : Male singers were superior to untrained males in coordination of respiratory and phonatory control on pitch, loudness, register change. Implication are offered regarding how the results might be applied to the voice therapy as well as singing training.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.7
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• pp.582-588
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• 2014

IMO and IALA have undertaken projects that GMDSS Modernization and E-navigation, which refer to "Future digital communications systems" for a more efficient transmission of voice and data communications in the VHF maritime mobile service. ITU has also resolved in WRC-07 Resolution 357 to study the use of spectrum-efficient technologies in order to provide for the operation of ship and port security and maritime safety systems. IALA and ITU WP5B have coordinated for the technical developments and the spectrum issues. Recommendation ITU-R M.1842-1 has approved by WP5B meeting. This revision provides a wideband data service both 50kHz and 100kHz in the VHF maritime mobile service. This paper has studied E-navigation, its needs for data exchange that includes explanations of the current methods for transmitting data by VHF that based in land mobile radio service. A further technologies trend is estimated for Recommendation ITU-R M.1842-1, that is based on the land mobile radio standards with some tailored to fit the needs of the maritime mobile service.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.138-147
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• 2022

Recently, chatbots have been applied in various fields and have shown good results, and many attempts to use chatbots in shopping mall product recommendation services are being conducted on e-commerce platforms. In this paper, for a conversation system that recommends a fashion that a user wants based on conversation between the user and the system and fashion image information, a transformer model that is currently performing well in various AI fields such as natural language processing, voice recognition, and image recognition. We propose a multimodal-based improved transformer model that is improved to increase the accuracy of recommendation by using dialogue (text) and fashion (image) information together for data preprocessing and data representation. We also propose a method to improve accuracy through data improvement by analyzing the data. The proposed system has a recommendation accuracy score of 0.6563 WKT (Weighted Kendall's tau), which significantly improved the existing system's 0.3372 WKT by 0.3191 WKT or more.