• 대한통합의학회지
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• 제9권1호
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• pp.41-48
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• 2021

Purpose : The purpose of this study is to find out if it helps to improve static balance ability and weight bearing rate for chronic stroke patients with poor balance in clinical intervention through a method of correcting movement errors while performing a task by vibrotactile bio-feedback providing pressure information. Methods : Fifteen chronic stroke patients (12 male and 3 female) were participated in this study. To examine the effects of vibrotactile bio-feedback and general standing without bio-feedback on static balance ability and weight distribution symmetric index in all subjects randomized with R Studio. The static balance ability and weight distribution symmetric index of the participants was evaluated using a force plate. A paired t-test was used for comparison of each conditions. Statistical significance was set at α=0.05. Results : The comparisons of static balance ability and weight distribution symmetric index in chronic stroke patients after two different condition are as follows. In the static balance ability and weight distribution symmetric index, the vibrotactile feedback providing pressure information showed a significant difference compared to none feedback (p<.001). Conclusion : The vibrotactile bio-feedback providing pressure information in real time can support an improve in static balance ability, uniform weight bearing rehabilitation in chronic stroke patients. In the future, it is hoped that a follow-up study that provides a better direction of intervention compared to various feedback interventions commonly used in clinical practice.

• 유통과학연구
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• 제22권1호
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• pp.79-94
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• 2024

Purpose: The popularity of social media has altered how customers interact with businesses, and an increasing number of customers prefer to voice their complaints on social media. Bystanders can observe the customer complaint process on social media, but the impact of transparency on bystanders remains uncertain. Therefore, this study established and verified a model for defining the effect of transparency and service recovery types on bystanders. Research Design and Methodology: In this study, we used the internet survey platform "So Jump" to collect data. And we validated three studies with SPSS 26.0 and Smart PLS 4.0. Result: First, we showed that the transparency process (vs. result) is more likely to increase customer forgiveness and E-loyalty and reduce E-NWOM intention among bystanders. Second, customer forgiveness also plays a complementary mediating role between transparency and E-loyalty, as well as between transparency and E-NWOM intention. Finally, we found a modest interaction effect between transparency (process vs. result) and service recovery types (psychological vs. tangible vs. hybrid) on bystanders' customer forgiveness and E-loyalty. Conclusions: This study provides actionable recommendations for how service managers can effectively employ social media as a means for distributing feedback information to manage service recovery in the future.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권2호
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• pp.126-136
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• 2004

이 논문은 색상과 위치정보를 이용한 새로운 내용기반 영상검색 알고리즘을 제안한다. 이를 위해서. 질의가 주어졌을 경우, 데이타베이스의 검색공간을 줄일 목적으로 두 가지 종류의 색인 키(Key)를 제시하는데 하나는 영상의 고유한 색상 구성적 특성을 나타내는 주요 색상세트(MCS, Main Colors' Set)이고 다른 하나는 주요 색상마다의 분포 및 위치적 특성을 나타내는 분포 블록기호(DBS, Distribution Block Signature)이다. 이 두 가지 필터(Filter)를 연속적으로 적용하면 영상 데이터베이스로부터 잠재성이 높은 유사 후보 영상만을 걸러내게 된다. 이어서 보다 높은 검색성능을 얻기 위해 새롭게 제안한 쿼드모델 (Quad Modeling)과 유사도 피드백 메커니즘을 이용한다. 이 방법은 색상과 위치정보에 대한 가중치를 역동적으로 조절함으로써 검색성능을 향상시킨다. 실험을 통해서 제안된 알고리즘이 성공적으로 영상검색에 사용될 수 있음을 보인다.

• 대한산업공학회지
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• 제19권4호
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• pp.137-146
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• 1993

We consider single server feedback queueing systems with priorities. In the model, there are J stations and job classes. Jobs of class i arrive at station i according to a Poisson process, and have a general service time distribution. We derive the generating functions of the number of jobs at each station just after a busy period and the formula for the mean sojourn time that a specific tagged job spends at station j from its arrival to departure from the system.

• Journal of Communications and Networks
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• 제13권4호
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• pp.339-344
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• 2011

Base station coordination has received much attention as a means to reduce the inter-cell interference in cellular networks. However, this interference reducing ability comes at the expense of increased feedback, backhaul load and computational complexity. The degree of coordination is therefore limited in practice. In this paper, we explore the trade-off between capacity and feedback load in a cellular network with coordination clusters. Our main interest lies in a scenario with multiple fading users in each cell. The results indicate that a large fraction of the total gain can be achieved by a significant reduction in feedback. We also find an approximate expression for the distribution of the instantaneous signal to interference-plus-noise ratio (SINR) and propose a new effective scheduling algorithm.

• 한국정밀공학회지
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• 제24권10호
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• pp.137-145
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• 2007

The purpose of this study is developing a virtual bicycle system for improving the ability of postural balance control for adults in various age groups. The system consists of an exercise bicycle that allows tilt in accordance with the postural balance of the subject in the system, a visual display that shows virtual road, and a visual feedback system. The rider of the system tries to maintain balance on the bicycle with a visual feedback of a virtual road while the pedaling speed, the heading direction, and various weight distribution information are updated to the subject as visual feedbacks in the display. A series of experiments were performed with various subjects to find the factors related to postural balance control in the system. The related parameters obtained were weight shift, magnitude of the deviation from the center of the virtual road, and variables related to the movement of the center of pressure. The results found that the ability to control postural balance in the system improved with the presentation of visual feedback information of the distribution of weight. It was also found that the general performance of the subject on balance in the system improved after ten days long training. The results show that the newly developed system can be used for the diagnosis of postural balance as well as for the stimulation of various senses such as vision and somatic sense in the field of rehabilitation training.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.535-538
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• 2002

공진기내에 음향광학소자(AOM)를 사용하여 FSF(Frequency-shifted feedback) 레이저를 수치해석 하였다. 출력 스펙트럼의 Comb 대역폭은 첨두 스펙트럼 세기에서의 순간 발진 주파수와 내부공진기 전계의 Wigner-Ville 분포로부터 유도된 순간 스펙트럼 세기의 식을 이용하여 분석한다. Comb 대역폭은 포화-확산된 대역폭과 FSF 동작에 유도되는 전체 공진 모드의 곱으로 정의된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.85-88
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• 2002

In this paper, the proposed watermark algorithm is based on energy distribution of the subband coefficients in the frequency domain and edge of the original image in the spacial domain. Out of these information, the KeyMap which decides the embedded position of watermark is produced. And then the binary watermark is embedded into the wavelet coefficient of LL3 subband using KeyMap and LFSR(Linear Feedback Shift Register).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1785-1801
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• 2017

In recent years, image encryption algorithms have been developed rapidly in order to ensure the security of image transmission. With the assistance of our previous work, this paper proposes a novel chaotic image encryption algorithm based on self-adaptive model and feedback mechanism to enhance the security and improve the efficiency. Different from other existing methods where the permutation is performed by the self-adaptive model, the initial values of iteration are generated in a novel way to make the distribution of initial values more uniform. Unlike the other schemes which is on the strength of the feedback mechanism in the stage of diffusion, the piecewise linear chaotic map is first introduced to produce the intermediate values for the sake of resisting the differential attack. The security and efficiency analysis has been performed. We measure our scheme through comprehensive simulations, considering key sensitivity, key space, encryption speed, and resistance to common attacks, especially differential attack.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.3434-3439
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• 2015

정보이론적 학습의 한 성능기준인 두 오차확률분포간 유클리드거리(MEDE)는 비선형 (결정 궤환, DF) 등화 알고리듬에 채택되었고 심각한 채널 왜곡과 충격성 잡음이 있는 환경에서 탁월한 성능을 보였다. 그러나 이 MEDE-DF 알고리듬은 과중한 계산 복잡성이라는 문제를 지니고 있다. 이 논문에서는 MEDE-DF 알고리듬을 위한 반복적 ED를 먼저 유도하고 그 다음 전후방 영역에 대해 가중치 기울기를 반복적으로 추정하는 식을 유도하였다. MEDE-DF 알고리듬의 반복적 기울기 추정방식의 효과를 입증하기위해 곱셈 계산량을 비교하였고 충격성 잡음과 수중 통신 환경에서 모의 실험한 MSE 성능 결과를 비교하였다. 제안한 DF 방식과 기존의 MEDE-DF 알고리듬의 곱셈 계산량 비는 샘플사이즈 N 에 대해 $2(9N+4):2(3N^2+3N)$로 나타나면서도 충격성 잡음과 수중통신 채널환경에서 동일한 MSE 학습 성능을 유지하였다.