• The Journal of Engineering Research
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• v.1 no.1
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• pp.41-48
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• 1997

In this paper, we wxtend DMSA system to support multimedia traffic more efficiently by incorporating a priority scheme. we divide network stations into two types: asynchronous and isosynchronous stations, and we give a priority to the isosynchronous stations over the asynchronous stations by imposing a time-out constraint on the asynchronous stations . we derive the maximum number of isosynchronous stations the proposed priority scheme can support simultaneously and the maximum bandwidth that can be utilized by asynchronous stations in the presence of isosynchronous traffic. We also provide simulation results for the mixed voice and data traffic, and compare them to the analytic results.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.4
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• pp.191-206
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• 2018

Purpose : This study investigated the correlation between speech intelligibility and acoustic measurements of speech sounds produced by the children with speech sound disorders and children without any diagnosed speech sound disorder. Methods : A total of 60 children with and without speech sound disorders were the subjects of this study. Speech samples were obtained by having the subjects? speak meaningful words. Acoustic measurements were analyzed on a spectrogram using the Multi-speech 3700 program. Speech intelligibility was determined according to a listener's perceptual judgment. Results : Children with speech sound disorders had significantly lower speech intelligibility than those without speech sound disorders. The intensity of the vowel /u/, the duration of the vowel /${\omega}$/, and the second formant of the vowel /${\omega}$/ were significantly different between both groups. There was no difference in voice onset time between the groups. There was a correlation between acoustic measurements and speech intelligibility. Conclusion : The results of this study showed that the speech intelligibility of children with speech sound disorders was affected by intensity, word duration, and formant frequency. It is necessary to complement clinical setting results using acoustic measurements in addition to evaluation of speech intelligibility.

• Current Optics and Photonics
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• v.3 no.2
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• pp.150-153
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• 2019

Larynx cancer is a potentially terminal and severe type of neck and head cancer in which malignant cells start to grow and spread upwards in the larynx, or voice box. Smoking tobacco, drinking hot beverages and drinking alcohol are the main risk factors for these tumors. In this study, we aimed to develop a precise, accurate and rapid chemometrics assisted Raman spectroscopy method for diagnosis of larynx cancer in deparaffinized tissue samples. In the proposed method, samples were deparaffinized and 20 microns of each tissue were located on a coverslip. Both healthy (n = 13) and cancerous tissues (n = 13) were exposed to a Raman laser (785 nm) and excitations were recorded between wavenumbers of $50{\sim}1500cm^{-1}$. An Orthogonal Partial Least Square algorithm was applied to evaluate the Raman spectrum obtained. Sensitivity and specificity of the proposed method is high enough with the aid of Principal Component Analysis (PCA) to test the whole model. Healthy and cancerous tissues were accurately and precisely clustered. A rapid, easy and precise diagnosis algorithm was developed for larynx cancer. By this method, some useful data about differences in biomolecules of each group (phospholipids, amides, tyrosine, phenylalanine collagen etc.) was also obtained from the spectra. It is claimed that the optimized method has a great potential for clustering and separating tumor tissues from healthy ones. This novel, rapid, precise and objective diagnosis method may be an alternative for the conventional methods in literature for diagnosis of larynx cancer.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.1
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• pp.1-8
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• 2021

Human vocal cords vibrate as quickly as 100-250 times per second, so it is impossible to observe them with normal endoscopic diagnostic equipment. High-speed videolaryngoscopy (HSV) allows the visualization of non-periodic vibratory motion of vocal fold beyond the limitation of videostroboscopy. New developed post-processing methods that converts HSV to two-dimensional videokymography (2D VKG) using U-medical image-processing software can provide quantitative information on vocal fold mucosa vibration. Multifunctional laryngeal examination system is composed of 3 kinds of examinations such as HSV, 2D scanning digital kymography (2D DKG) and line scanning digital kymography (DKG). Evaluation of entire vocal cord vibratory pattern in each cord is possible using 2D DKG and a faster and more reliable quantitative information can be obtained. As this system is used in clinical and research, it is expected to bring much advances to the diagnosis of voice disorders. In this review, I will introduce the principles and advantages on examination of the vocal fold vibration, which is in the spotlight recently, and proceed with the literature review.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.2
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• pp.115-118
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• 2022

Fibrolipomas are a rare microscopic variant of lipomas, characterized by mature adipose tissue interspersed with dense fibrous connective tissue. These lesions are rarely observed in the head and neck region and represent <0.6% of all benign tumors of the larynx and hypopharynx. Their clinical presentation depends on the location and size of lesions. Patients present with variable symptoms; however, fibrolipomas of the larynx and hypopharynx are clinically important because these tumors can cause unpredictable airway obstruction, particularly during general anesthesia induction. We present a case of a hypopharyngeal fibrolipoma in a 61-year-old patient with frequent dyspnea, dysphagia, and muffled voice. Laryngoscopy revealed a well-demarcated pedunculated ovoid mass involving the larynx. We performed laryngomicrosurgery using a carbon dioxide laser for surgical excision and subsequent evaluation confirmed the diagnosis of fibrolipoma. We report a case of hypopharyngeal fibrolipoma, together with a literature review.

• Journal of Korea Multimedia Society
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• v.23 no.8
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• pp.1099-1107
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• 2020

The need for customized services providing real-time subway information through mobile devices for the blind using subway as their primary transportation method is becoming more essential. Therefore, this study is aimed at developing a mobile service to provide real-time subway information by displaying with braille and utilizing Dot Watch. The process of real-time subway information guidance mobile service is as follows: the route confirmation stage, the ride waiting & judgment stage, the on-the-go stage, and lastly, the off-road phase & wrong path state. The service provides real-time appropriate information to the visually impaired people for each situation. It receives subway information through API provided by Seoul Metropolitan Government and ODSay API. The service is developed and coded with in Java using Android Studio, and the communicating method with Dot Watch was done using Bluetooth. The usability evaluation was conducted in terms of efficiency, effectiveness, and satisfaction. The evaluation methods mentioned above were carried out by testees, and feedback was given. They assessed that the information provided was useful but still unstable to use the system. It is expected that actual usability will increase if our study is supplemented using voice output function.

• Knowledge Management Research
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• v.21 no.1
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• pp.197-210
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• 2020

The smart speaker includes an AI assistant function in the existing portable speaker, which enables a person to give various commands using a voice and provides various offline services associated with control of a connected device. The speed of domestic distribution is also increasing, and the functions and linked services available through smart speakers are expanding to shopping and food orders. Through text mining-based customer review analysis, there have been many proposals for identifying the impact on customer attitudes, sentiment analysis, and product evaluation of product functions and attributes. Emotional investigation has been performed by extracting words corresponding to characteristics or features from product reviews and analyzing the impact on assessment. After obtaining the topic from the review, the effect on the evaluation was analyzed. And the market competition of similar products was visualized. Also, a study was conducted to analyze the reviews of smart speaker users through text mining and to identify the main attributes, emotional sensitivity analysis, and the effects of artificial intelligence attributes on product satisfaction. The purpose of this study is to collect blog posts about the user's experiences of smart speakers released in Korea and to analyze the attitudes of customers according to their attributes. Through this, customers' attitudes can be identified and visualized by each smart speaker product, and the positioning map of the product was derived based on customer recognition of smart speaker products by collecting the information identified by each property.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7C
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• pp.962-970
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• 2004

This paper presents an efficient implementation of the 2.4 kbps EHSX(Enhanced Harmonic Stochastic Excitation) speech coder on a TMS320C6701$^{TM}$ floating-point digital signal processor. The EHSX speech codec is based on a harmonic and CELP(Code Excited Linear Prediction) modeling of the excitation signal respectively according to the frame characteristic such as a voiced speech and an unvoiced speech. In this paper, we represent the optimization methods to reduce the complexity for real-time implementation. The complexity in the filtering of a CELP algorithm that is the main part for the EHSX algorithm complexity can be reduced by converting program using floating-point variable to program using fixed-point variable. We also present the efficient optimization methods including the code allocation considering a DSP architecture and the low complexity algorithm of harmonic/pitch search in encoder part. Finally, we obtained the subjective quality of MOS 3.28 from speech quality test using the PESQ(perceptual evaluation of speech quality), ITU-T Recommendation P.862 and could get a goal of realtime operation of the EHSX codec.c.

• Journal of Korean Society for Quality Management
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• v.43 no.4
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• pp.589-606
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• 2015

Purpose: In developing new products, reducing performance variation is important for competitiveness factors such as quality, cost, and delivery. This paper aims at evaluating three performance variations; measurement, performance evaluation, and manufacturing variations, and then improving product and process design, focused on paper helicopter making case study. Methods: For measurement system analysis, gage R&R (repeatability and reproducibility), linearity, stability are evaluated. Since gage R&R are not satisfactory, the measurement system is improved by adopting voice memos application of iPhone and providing standard measurement procedure. To evaluate performance variation, product deterioration and environment factor (wind speed) is considered. Since the existing design is sensitive to these noise factors, a new product design is developed, which is proven to be robust to the noise factors. Finally, manufacturing variations are evaluated with five factors which can cause variation in flight time. To reduce the impact of three significant factors, three improvement methods are applied. Results: Three performance variations are evaluated and robust paper helicopter design is presented. Conclusion: To reduce measurement and process variations, improved measurement method and paper helicopter making procedure are proposed. A new product design is also presented which is robust to deterioration and environmental variation. This paper is expected to benefit students and practitioners who want to have hands-on knowledge on new product quality improvement.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.2
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• pp.57-63
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• 2021

The purpose of this study is to develop a Smart Helmet to safeguard forest firefighting crews and provide on-site information in real time. The Smart Helmet for forest firefingting crews is equipped with a camera, video/voice communication module, GPS, Bluetooth, and LTE module to promote the safety of them, and through the Smart Helmet, the site situation is is transmitted in real time, and full duplex communication is possible. As a result of testing using the Smart Helmet, the control center was able to receive on-site information and communication with on-site forest firefighting crews. Through site evaluation and user evaluation, it was confirmed that the Smart Helmet needs to be improved. The developed Smart Helmet can be used in various ways in forest disasters and forest industry.