• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.617-626
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• 2008

Opportunistic Beamforming (OBF) offers a way to provide the multiuser diversity even in slow fading channel by using randomly generated beam weights, leading to the substantially reduced feedback in the form of the instantaneous SNR from users. In spite of the advantage of the reduced feedback, the imperfect channel estimation might influence the quality of the estimated SNR and channel scheduler so bad that the selected AMC level would be higher than the achievable rate of the actual channel, resulting the corruption of transmitted packet. In this paper, we propose a conservative link adaptation, where the estimated SNR is scaled down by a conservative factor which minimizes the variance of the maximum difference between the actual channel SNR and the resultant SNR. To support the proposed scheme, we analyze the statistics of the difference of the channel SNR and the estimated SNR. Simulation results show that the introduction of conservative factor achieves more than two-fold performance improvement in the presence of channel estimation error and the fairness of PF scheduler is maintained when the least squared channel estimator is applied.

• Journal of Internet Computing and Services
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• v.14 no.4
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• pp.85-90
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• 2013

Currently, the electric fire prediction system uses PIC(Peripheral Interface Controller) for controller microprocessor. PIC has a slower computing speed than DSP does, so its real-time computing ability is inadequate. So with the basic characteristics waveform during arc generation as the standard reference, the comparison to this reference is used to predict and alarm electric fire from arc. While such alarm can be detected and taken care of from a remote central server, that prediction error rate is high and remote control in mobile environment is not available. In this article, the arc detection of time domain and frequency domain and wavelet-based adaptation algorithm executing the adaptation algorithm in conversion domain were applied to develop an electric fire prediction system loaded with new real-time arc detection algorithm using DSP. Also, remote control was made available through iPhone environment-based app development which enabled remote monitoring for arc's electric signal and power quality, and its utility was verified.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.413-425
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• 2019

This study was conducted to identify factors affecting depression in junior nursing students(JNS). The number of the participants was 144 at a college in S and G city. The data were collected using questionnaires about somatic symptoms(SS), sleep quality, stress, adaptation to college life(AC), depression. Mean score of depression was 18.89, 58.3% are experiencing depression that requires clinical treatment. The significant predictors of JNS were levels of depression AC(β=-.503, p=.000) and SS(β=.263, p=.000) respectively, explaining 58.9% of variance. In order to control the depressive symptoms of JNS, it is necessary to diagnose basic learning ability from the beginning of admission and provide guidance management plans to help students adapt to academic activities by providing customized programs for each level to improve learning ability. It is necessary to develop and apply various intervention programs to alleviate physical symptoms such as fatigue/low energy experienced by JNS.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.402-411
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• 2014

This study suggests the method of green infrastructure (GI) application which helps proper distribution of structural GI and non-structural GI by using land characteristics assessment and performs the case study. Land assessment standard consists of land cover type, fragmentation degree, proximity degree to residential districts, and cluster degree of fragmented areas which represents the quality of green network. The result of assessment proposes the land suitability to preserve or develop and it can be utilized to choose the type of the green infrastructures.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.95-105
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• 2009

A method was proposed which employed control of the drop location of fertilizer particles on a spinner disc to optimize the spread pattern uniformity. The system contained an optical sensor as a feedback mechanism, which measured discharge velocity and location, as well as particle diameters to predict a spread pattern of a single disc. Simulations showed that the feed gate adaptation algorithm produced high quality patterns for any given application rate in the dual disc spreader. The performance of the feed gate control method was assessed using data collected from a Sulky spinner disc spreader. The results showed that it was always possible to find a spread pattern with an acceptable CV lower than 15%, even though the spread pattern was obtained from a rudimentary flat disc with straight radial vanes. A mathematical optimization method was used to find the initial parameter settings for a specially designed experimental spreading arrangement, which included the feed gate control system, for a given flow rate and swath width. Several experiments were carried out to investigate the relationship between the gate opening and flow rate, disc speed and particle velocity, as well as disc speed and predicted landing location of fertilizer particles. All relationships found were highly linear ($r^2$ > 0.96), which showed that the time-of-flight sensor was well suited as a feedback sensor in the rate and uniformity controlled spreading system.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.555-564
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• 2007

Discrete cosine transform (DCT) coefficient dropping is well recognized as an efficient rate adaptation transcoding in motion-compensated (MC)-DCT based MPEG-compressed videos. However, in this scheme, the errors incurred by the DCT coefficient-dropping are propagated and often result in significant visual quality degradation. This paper presents two propositions describing well the statistical properties of propagated errors. That is, we propose that the DCT error of the current frame is not correlated to the propagated errors of the previous frames. We also propose that the overall distortions in a given frame can be approximated as the sum of the DCT error of the current frame and the propagated errors from the previous frames. Then, it is shown that several computer simulations with different video sequences verify the effectiveness of the proposed statistical analyses.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.185-190
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• 2003

Due to the rapid growth of Internet, means of communication with customers in a traditional customer support environment such as telephone calls are being replaced by mainly e-mail in a Web-based customer support system. Although such a Web-based support is efficient and promises potential benefits for firms, including reduced transaction costs, reduced time, and high quality of support, there are some difficulties associated with responding to many types of customer’s inbound e-mails appropriately .As many types of e-mail are received, considerable attention is being paid to methods for increasing the efficiency of managing and responding e-mails. This research proposes an intelligent system for managing customer’s inbound e-mails in organizations by applying case based reasoning technique for responding to various customers' inbound e-mails more effectively. In this approach, a case is represented as a frame-typed data structure corresponding to an inbound e-mail, keywords, and its reply e-mail. In the retrieval procedure, keywords and affinity set is developed to index a case, and then the case is represented as a vector, a case vector. Also, cosines value is calculated to measure the similarity between a new inbound e-mail and the cases in the case base. In the adaptation procedure, we provide several adaptation strategies to adapt and modify the retrieved case. The strategies guide to make an outbound e-mail using product databases, databases for customer support, etc. Additionally, the Web-based system architecture is proposed to implement our methodology. The proposed methodology and system will be helpful for developing more efficient Web-based customer support.

• Korea journal of population studies
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• v.31 no.3
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• pp.1-26
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• 2008

The main purpose of this paper is to explore the impacts of foreign wife status and social capital on fertility among a group of Chinese, Vietnamese and Japanese wives in Korea. Attention is focused on the argument that minority group status and immigrant social capital exerts an independent effect on fertility, apart from socioeconomic and demographic variables. It is hypothesized that the level and tempo of fertility of foreign wives reflect their social disadvantages and the adaptation process. Micro-data from two socio-demographic surveys were utilized to analyze the reproductive outcomes of foreign and native wives in Korea. Results of analyses reveal that foreign wives in Korea tend to have fewer children compared to native Korean women. It was found that a foreign wife's access to social capital significantly facilitates reproductive behavior. Those who engage themselves more in voluntary activities, have more friends in Korea, and possess better and higher-quality social networks tend to have more children. Foreign wives with a high degree of integration or assimilation to the new surroundings were also found to have more children than other foreign wives.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.10
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• pp.1000-1004
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• 2010

A large number of current language processing systems use a part-of-speech tagger for preprocessing. Most language processing systems required a tagger with the highest possible accuracy. Specially, the use of domain-specific advantages has become a hot issue in machine translation community to improve the translation quality. This paper addresses a method for customizing an HMM or LHMM based English tagger from general domain to specific domain. The proposed method is to semi-automatically customize the output and transition probabilities of HMM or LHMM using domain-specific raw corpus. Through the experiments customizing to Patent domain, our LHMM tagger adapted by the proposed method shows the word tagging accuracy of 98.87% and the sentence tagging accuracy of 78.5%. Also, compared with the general tagger, our tagger improved the word tagging accuracy of 2.24% (ERR: 66.4%) and the sentence tagging accuracy of 41.0% (ERR: 65.6%).

• PNF and Movement
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• v.20 no.2
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• pp.263-273
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• 2022

Purpose: Translation and adaptation involve cross-cultural and conceptual aspects; they are not simply based on linguistic equivalence. This study aimed to produce a conceptually equivalent Korean version of the motor activity log (K-MAL) for the upper extremities that can be applied across the Korean population and its cultures. Methods: Following the procedures used in the translation of other cross-cultural evaluation tools, and the five steps of the translation process, the motor activity log (MAL) was translated into Korean (K-MAL). We then examined the content validity of the K-MAL. Twenty-two rehabilitation professionals (11 males and 11 females, mean length of clinical career = 101.54 months) assessed the content validity of the K-MAL. The content validity ratio and content validity index were used to verify the content validity. Results: There were inconsistencies found in three sub-items in the MAL during the forward translation process. These inconsistencies were corrected, and the complete K-MAL was produced. The exact critical values of the content validity ratio and the content validity index of the K-MAL were 0.45-0.95 and 0.77-1.00, respectively. Conclusion: The K-MAL was successfully developed using a systematic methodology, which included translation, adaptation, and evaluation of the content validity. We expect that stroke rehabilitation professionals working in both clinical and research settings will apply the K-MAL when evaluating the amount and quality of use of the upper extremities in post-stroke patients in Korea.