• 디지털산업정보학회논문지
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• 제15권3호
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• pp.197-206
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• 2019

Telemarketing has been used in finance due to the reduction of offline channels. In order to select telemarketing target customers, various machine learning techniques have emerged to maximize the effect of minimum cost. However, there are problems that the class imbalance, which the number of marketing success customers is smaller than the number of failed customers, and the recall rate is lower than accuracy. In this paper, we propose a method that solve the imbalanced class problem and increase the recall rate to improve the efficiency. The hybrid sampling method is applied to balance the data in the class, and the stacked deep network is applied to improve the recall and precision as well as the accuracy. The proposed method is applied to actual bank telemarketing data. As a result of the comparison experiment, the accuracy, the recall, and the precision is improved higher than that of the conventional methods.

• 지능정보연구
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• 제28권3호
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• pp.23-43
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• 2022

AI(Artificial Intelligence)를 다양한 산업에서 접목하기 위해 알고리즘 선택에 대한 관심이 증가하고 있다. 알고리즘 선택은 대부분 데이터 과학자의 경험에 의해 결정되는 경우가 많다. 하지만 경험이 부족한 데이터 과학자의 경우 데이터셋 특성 기반의 메타학습(meta learning) 을 통해 알고리즘을 선택한다. 기존의 알고리즘 추천은 선정 과정이 블랙박스이기 때문에 어떠한 근거에 의해 도출되는지 알 수 없었다. 이에 따라 본 연구에서는 k-평균 군집분석을 활용하여 데이터셋 특성에 따라 유형을 나누고 적합한 분류 알고리즘과 클래스 불균형 해소 방법을 탐색한다. 본 연구 결과 네 가지 유형을 도출하였으며 데이터셋 유형에 따라 적합한 클래스 불균형 해소 방법과 분류 알고리즘을 추천하였다.

• The Journal of Korean Physical Therapy
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• 제27권6호
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• pp.392-399
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• 2015

Purpose: This study investigated whether the strength imbalance between two muscles can affect the score of EMG based biofeedback game, and whether the EMG based biofeedback game score can be used as predictable indicator of the degree of muscle balance alternating the conventional strength measuring equipment. Methods: 40 participated in this study. Biodex was used to measure the peak torque/weight in order to calculate the muscle strength balance index between plantar flexor and dorsiflexor of ankle joint. And muscle balance index (MBI) was calculated. The EMG biofeedback game scores of dorsiflexor and plantar flexor were acquired, so that the EMG electrodes were attached at tibialis anterior and gastrocnemius. The relationship between the game score and the muscle balance index were analyzed. Results: There was negative correlation between the muscle balance index between plantar flexor and dorsiflexor and the peak torque/weight of plantar flexor (r=-0.70). And there was negative correlation between the muscle balance index between plantar flexor and dorsiflexor and the game score of plantar flexor (r=-0.83). Conclusion: The EMG biofeedback game score had significant relationship with muscle imbalance at ankle joint, so it seems that the game score can be used for predicting the degree of muscle imbalance as a parameter.

• Journal of Information Processing Systems
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• 제14권3호
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• pp.569-589
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• 2018

Cloud computing, also known as "country as you go", is used to turn any computer into a dematerialized architecture in which users can access different services. In addition to the daily evolution of stakeholders' number and beneficiaries, the imbalance between the virtual machines of data centers in a cloud environment impacts the performance as it decreases the hardware resources and the software's profitability. Our axis of research is the load balancing between a data center's virtual machines. It is used for reducing the degree of load imbalance between those machines in order to solve the problems caused by this technological evolution and ensure a greater quality of service. Our article focuses on two main phases: the pre-classification of tasks, according to the requested resources; and the classification of tasks into levels ('odd levels' or 'even levels') in ascending order based on the meta-heuristic "Bat-algorithm". The task allocation is based on levels provided by the bat-algorithm and through our mathematical functions, and we will divide our system into a number of virtual machines with nearly equal performance. Otherwise, we suggest different classes of virtual machines, but the condition is that each class should contain machines with similar characteristics compared to the existing binary search scheme.

• Journal of Information Technology Applications and Management
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• 제28권3호
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• pp.109-125
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• 2021

For the government of president Moon's AI SW HRD policy, he proclaimed AI democracy that anyone can utilize artificial intelligence technology to spread AI education for the people of the country. Through cognitive map analysis, this study presents expected policy outcomes due to the input of policy factors to overcome crisis factors and utilize opportunity factors. According to the cognitive guidance analysis, first, the opportunity factor is recognized as accelerating the digital transformation to Covid 19 if AI SW HRD is well nurtured. Second, the crisis factor refers to the rapid paradigm shift caused by the intelligence information society, resulting in job losses in the manufacturing sector and deepening imbalance in manpower supply and demand, especially in the artificial intelligence sector. Third, the comprehensive cognitive map shows a circular process for creating an AI SW ecosystem in response to threats caused by untact caused by Corona and a circular process for securing AI talent in response to threats caused by deepening imbalance in manpower supply and demand in the AI sector. Fourth, in order to accelerate the digital circulation that has been accelerated by Corona, we found a circular process to succeed in the Korean version of digital new deal by strengthening national and corporate competitiveness through AI-utilized capacity and industrial and regional AI education. Finally, the AI utilization empowerment strengthening rotation process is the most dominant of the four mechanisms, and we also found a relatively controllable feedback loop to obtain policy outputs.

• 한국콘텐츠학회논문지
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• 제19권7호
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• pp.36-46
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• 2019

주식시장이 효율적이라면 아무리 잘 고안된 투자전략이라도 시장의 평균 수익을 장기적으로 초과하는 것은 어렵다. 본 연구의 목적은 일부 시장 참여자들 사이에 회자되고 있는 호가잔량 정보효과를 이용하여 장기적으로 높은 수익을 얻을 수 있는지를 실증 분석하는데 있다. 이를 위하여 호가잔량정보를 이용하는 데이트레이딩 전략을 제안하고, 2001년부터 2018년까지의 코스피200 주가지수선물시장에 적용하여 과연 꾸준하게 돈을 벌 수 있는지를 분석하였다. 구체적으로 매수강도지수가 50% 이상이면 가격이 상승할 것으로 예상하고, 반대로 매수강도지수가 50% 미만이면 가격이 하락할 것으로 예상하여 각각 매수포지션과 매도포지션을 진입하여 수익성을 검증하였다. 실증분석 결과는 거래에 수반되는 거래비용을 제하고도 연 평균 71% 이상의 매우 높은 수익을 보여주고 있다. 발생된 수익 역시 분석 기간 전체에서 장기적, 안정적으로 나타나고 있음을 밝혔다. 유전자알고리즘을 이용하여 제안된 투자전략의 수익성을 개선함으로서, 호가잔량정보를 이용하는 투자자들에게 많은 도움이 될 것으로 기대된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3583-3598
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• 2019

In order to improve the reliability and repair efficiency of distributed storage systems, minimum bandwidth regenerating (MBR) codes based on cyclic variable fractional repetition (VFR) codes are constructed in this thesis, which can repair failed nodes accurately. Specifically, in order to consider the imbalance of data accessed by the users, cyclic VFR codes are constructed according to that data with different heat degrees are copied in different repetition degrees. Moreover, we divide the storage nodes into groups, and construct MBR codes based on cyclic VFR codes to improve the file download speed. Performance analysis and simulation results show that, the repair locality of a single node failure is always 2 when MBR codes based on cyclic VFR codes are adopted in distributed storage systems, which is obviously superior to the traditional MBR codes. Compared with RS codes and simple regenerating codes, the proposed MBR codes based on cyclic VFR codes have lower repair locality, repair complexity and bandwidth overhead, as well as higher repair efficiency. Moreover, relative to FR codes, the MBR codes based on cyclic VFR codes can be applicable to more storage systems.

• 한국전자파학회논문지
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• 제19권4호
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• pp.436-441
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• 2008

본 논문은 최근 발표된 이중 모드 링-공진기를 이용한 Balun-BPF를 3-단자 회로망 분석 방법을 이용하여 전체 어드미턴스 파라미터를 유도하고 이를 이용하여 Balun의 특성을 만족함을 수식적으로 증명하였다. BPF의 표준 설계법을 적용하여 손쉽게 임의의 특성을 갖는 Balun-BPF 설계가 가능하도록 Balun 동작 상태에서의 이미턴스 슬로프 파라미터를 도출하고, Balun-BPF 양단의 감쇄극 주파수를 예측하는 방법을 제시하였다. 회로 시뮬레이션과 실제 제작 측정을 통해 제안된 해석식들을 검증하였다. 제작된 Balun-BPF는 중심 주파수 2.46 GHz에서 71 MHz 대역폭과 삽입 손실 0.92 dB를 가지며, $174{\sim}181^{\circ}$의 위상 특성과 0.5 dB 이내의 크기 특성을 나타내었다.

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.268-273
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• 2013

In this paper, we propose a document classification model using Web documents as a part of the training corpus in order to resolve the imbalance of the training corpus size per category. For the purpose of retrieving the Web documents closely related to each category, the proposed document classification model calculates the matching score between word features and each category, and generates a Web search query by combining the higher-ranked word features and the category title. Then, the proposed document classification model sends each combined query to the open application programming interface of the Web search engine, and receives the snippet results retrieved from the Web search engine. Finally, the proposed document classification model adds these snippet results as Web documents to the training corpus. Experimental results show that the method that considers the balance of the training corpus size per category exhibits better performance in some categories with small training sets.

• 한국통신학회논문지
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• 제40권7호
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• pp.1457-1467
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• 2015

해양 통신을 위한 VHF 대역 데이터 통신 시스템(VHF Data Exchange System: VDES)은 송수신단의 종류에 따라 서로 다른 주파수 대역을 사용하도록 설계되어 있으며, 육상국으로부터 멀리 떨어진 선박국에게 육상국과 연결성을 보장하기 위해 제안된 ASO-TDMA (Ad-hoc Self-Organizing TDMA) MAC 프로토콜을 이용하여 다중-홉 통신을 수행하는 경우에 주파수 채널간 부하 불균형 문제가 발생한다. 본 논문에서는 이러한 주파수 채널간 부하 불균형 문제를 해결하기 위해 통계적 기하(stochastic geometry) 모델링을 도입한다. 이를 기반으로 동일 홉 영역에서의 공간적 자원 재사용률을 분석하고, 각 홉 영역 별로 최적의 자원 할당을 통해 채널간의 부하 불균형 문제를 해결하여 자원 활용도를 극대화하는 것을 보인다.