• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.4
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• pp.156-163
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• 1996

In this paper, we described the implementation and the sound quality assessment of a real-time stereo audio codec using TMS320C40 DSP (digital signal processing) chip for low bitrte and high quality audio. We implemented hardware and software in order to overcome a real-time processing problem of audio compression algorithm that can be produced by largely recursive computing and complexity of the process. We have studied five types of distortion that can be produced by perceptual coding and the codec was evaluated by eight test musics that are selected in SQAM (sound quality assessment material) 422-2-4-2 produced by EBU (european broadcast union). The subjective listening tests were carried out on the codec quality and preformance by double blind method in a listening room with eleven listeners. As a result, 5 grade-impairment scale was scored under minus one and the codec quality was evaluated to be perceptible, but not annoying.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3E
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• pp.56-61
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• 1997

In this paper, we describe a real-time implementation of a multi-channel auido codec system that is based on the MPEG-1 audio algorithm. The major feature of this system is that it has a flexible multi-DSP system that can be adapted for various applications with using up to four TMS320C40 DSPs. The purpose of this paper is to present the problems of the system and is to describe the optimized methods to solve the problems in the view of hardware and software. Our audio codec is composed of an encoder an a decoder system and the bit rate of bitstream is up to 384 kbps. Fast input/output interfaces, DSP overloads, and inter-DSP communications methods with high speed are considered in multi-DSP H/W. Also, to run real-time in S/W, optimizing methods of algorithm are considered. After implementation of system, the subjective assessment method, and 'triple stimulus/hidden reference/double blind' that recommended by ITU-R TG10/3 is adopted for the quality of our system. All test items except one are awarded difference grades(diffgrade) better than 1-. Form the results, multi-channel audio system can be used for HDTV service.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.155-158
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• 2007

In this paper, we solved the underestimation problem of PSNR, which is caused by repeated frames, by easily synchronizing original and decoded frames using the proposed marks. Also we propose full-reference system which can be applied for measuring the quality of various kinds of video communication systems, e.g. wireless handsets, mobile phones and applications for PC. In addition, we propose a new video quality assessment metric using video communication parameters, i.e. frame rate and delay. According to the experiments, the proposed metric is not only appropriate for real-time video communication systems but also shows better correlation with the subjective video quality assessment than PSNR. The proposed measuring system and metric can be effectively used for measuring and standardizing the video quality of future communications.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.93-101
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• 2022

Purpose: This study compared the effectiveness of complementary metal-oxide semiconductors (CMOS) and photostimulable phosphor (PSP) plates as intraoral imaging systems in terms of time efficacy, patient comfort, and subjective image quality assessment in real clinical settings. Materials and Methods: Fifty-eight patients (25 women and 33 men) were included. Patients were referred for a full-mouth radiological examination including 1 bitewing radiograph (left and right) and 8 periapical radiographs for each side (left maxilla/mandible and right maxilla/mandible). For each patient, 1 side of the dental arch was radiographed using a CMOS detector, whereas the other side was radiographed using a PSP detector, ensuring an equal number of left and right arches imaged by each detector. Clinical application time, comfort/pain, and subjective image quality were assessed for each detector. Continuous variables were summarized as mean±standard deviation. Differences between detectors were evaluated using repeated-measures analysis of variance. P<0.05 was accepted as significant. Results: The mean total time required for all imaging procedures with the CMOS detector was significantly lower than the mean total time required for imaging procedures with PSP (P<0.05). The overall mean patient comfort scores for the CMOS and PSP detectors were 4.57 and 4.48, respectively, without a statistically significant difference (P>0.05). The performance of both observers in subjectively assessing structures was significantly higher when using CMOS images than when using PSP images for all regions (P<0.05). Conclusion: The CMOS detector was found to be superior to the PSP detector in terms of clinical time efficacy and subjective image quality.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.18-30
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• 2015

As the speed of networks that subscribers can use has greatly increased, demand for high-quality broadcast content, such as from Internet Protocol Television (IPTV) and Video on Demand (VoD), is likewise increasing. Therefore, while broadcasters are increasing content and channels, they are striving to improve consumer quality of experience (QoE) to differentiate themselves from competitors, including by producing higher physical-quality content. Recently, subjective measurement methods have been internationally standardized as the most reliable approach for measuring and evaluating IPTV QoE. However, a majority of these methods are performed in experimental environments and are based on the extremely brief viewing period of approximately ten seconds using original reference videos. It is actually difficult to apply standard evaluation methods based on a ten-second viewing interval to assess real broadcast watching of IPTV or other services that involve a longer time (i.e., more than thirty minutes). In this paper, we therefore propose a method that accommodates actual viewing environments. Using the mean opinion score, we experimentally analyze the effects of evaluation interval changes under actual conditions in which IPTV service is provided. In addition, we propose improvements by applying the results into actual live broadcast IPTV service and by analyzing consumer service QoE.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2513-2530
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• 2021

With the fast development of information and communication technologies, video streaming services and applications are increasing rapidly. However, the network condition is volatile. In order to provide users with better quality of service, it is necessary to develop an accurate and low-complexity model for Quality of Experience (QoE) prediction of time-varying video. Memory effects refer to the psychological influence factor of historical experience, which can be taken into account to improve the accuracy of QoE evaluation. In this paper, we design subjective experiments to explore the impact of Short-Term Memory (STM) on QoE. The experimental results show that the user's real-time QoE is influenced by the duration of previous viewing experience and the expectations generated by STM. Furthermore, we propose analytical models to determine the relationship between intrinsic video quality, expectation and real-time QoE. The proposed models have better performance for real-time QoE prediction when the video is transmitted in a fluctuate network. The models are capable of providing more accurate guidance for improving the quality of video streaming services.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.567-574
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• 2013

Although Korea coastal area has the increasing potential marine accident due to frequent ship's encounter, increased vessel traffic and large vessel, there is no specific model to evaluate the navigating vessel's risk considering the domestic traffic situation. The maritime transport environmental assessment is necessary due to the amended maritime traffic law. However, marine safety diagnosis is now carried out by foreign model. In this paper, therefore, we suggest a domestic traffic model reflecting the characteristics of korea coastal area and navigator's risk as we named PARK(Potential Assessment of Risk) model. We can evaluate the subjective risk by establishing the model and model output into maritime risk exposure system. To evaluate this model's effectiveness, we used ship handling simulation and applied, analyzed collision accident which occurred in korea coastal area. And also, we applied integrated to an ECDIS program for monitoring traffic risk of vessels with real time based AIS data and apply to evaluate traffic risk in busan harbor waterway. As a result, we could evaluate busan harbor waterway risk effectively.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.1
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• pp.38-44
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• 2021

Purpose: Digital communication is becoming increasingly important in clinical practice and research. The finding that stool consistency can be evaluated similarly using either "in vivo" or photographic material by health care professionals will decrease subjective interpretation by parents. The primary outcome of this study was the reliability of stool consistency scoring using the Brussels Infant and Toddler Stool Scale (BITSS) between fresh stools and their photos; the secondary outcome was the inter-rater reliability based on the fresh stools. Methods: Fresh stool samples from healthy children were collected in a day care center. These stools, and one month later the corresponding photos presented in a random order, were presented to 14 observers. Reliabilities were analyzed using absolute agreements and weighted and unweighted Cohen's κ. Results: In total, 202 samples were rated 576 times. Absolute agreement between photographic and real time assessment ranged between 71.1% and 83.3% among observers. This corresponded with substantial agreement (unweighted κ=0.70 [95% CI, 0.61-0.78]; weighted κ=0.86 [95% CI, 0.78-0.88]). The inter-observer agreement showed similar percentages of absolute agreement (81.4-82.0%) and κ-values corresponding with fair-to-moderate agreement. Conclusion: Our findings suggest that the assessment of fresh stool consistency can also reliably be done on photographic material when using the BITSS. This opens opportunities in scientific surroundings and in our daily life communication with parents and caretakers.

• ETRI Journal
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• v.38 no.3
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• pp.425-434
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• 2016

A novel average magnitude difference function (AMDF)-based pitch detection scheme (PDS) is proposed to achieve better performance in speech quality. A performance evaluation of the proposed PDS is carried out through both a simulation and a real-time implementation of a speech analysis-synthesis system. The parameters used to compare the performance of the proposed PDS with that of PDSs that are based on either a cepstrum, an autocorrelation function (ACF), an AMDF, or circular AMDF (CAMDF) methods are as follows: percentage gross pitch error (%GPE); a subjective listening test; an objective speech quality assessment; a speech intelligibility test; a synthesized speech waveform; computation time; and memory consumption. The proposed PDS results in lower %GPE and better synthesized speech quality and intelligibility for different speech signals as compared to the cepstrum-, ACF-, AMDF-, and CAMDF-based PDSs. The computational time of the proposed PDS is also less than that for the cepstrum-, ACF-, and CAMDF-based PDSs. Moreover, the total memory consumed by the proposed PDS is less than that for the ACF- and cepstrum-based PDSs.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.86-102
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• 2024

Early diagnosis, accurate assessment, and localization of peritoneal metastasis (PM) are essential for the selection of appropriate treatments and surgical guidance. However, available imaging modalities (computed tomography [CT], conventional magnetic resonance imaging [MRI], and 18fluorodeoxyglucose positron emission tomography [PET]/CT) have limitations. The advent of new imaging techniques and novel molecular imaging agents have revealed molecular processes in the tumor microenvironment as an application for the early diagnosis and assessment of PM as well as real-time guided surgical resection, which has changed clinical management. In contrast to clinical imaging, which is purely qualitative and subjective for interpreting macroscopic structures, radiomics and artificial intelligence (AI) capitalize on high-dimensional numerical data from images that may reflect tumor pathophysiology. A predictive model can be used to predict the occurrence, recurrence, and prognosis of PM, thereby avoiding unnecessary exploratory surgeries. This review summarizes the role and status of different imaging techniques, especially new imaging strategies such as spectral photon-counting CT, fibroblast activation protein inhibitor (FAPI) PET/CT, near-infrared fluorescence imaging, and PET/MRI, for early diagnosis, assessment of surgical indications, and recurrence monitoring in patients with PM. The clinical applications, limitations, and solutions for fluorescence imaging, radiomics, and AI are also discussed.