• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제11권4호
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• pp.157-162
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• 2022

오늘날 대부분의 데이터는 데이터베이스(database: DB)에 저장된다. 이러한 DB 환경에서 사용자는 자신이 원하는 데이터를 찾아줄 것을 DB에게 요청하게 된다. DB 질의 중 유사도 질의는 DB 사용자가 원하는 조건으로 유사도가 포함되어 있는 것을 말한다. 그러나 유사도 질의를 처리하기 위한 과정은 처리 레코드의 범위를 줄일 수 있는 색인을 이용하기 힘들어 테이블의 전체 레코드에 대해서 매번 유사도를 계산하는 비용이 높다. 본 논문은 이러한 문제점을 해결하기 위하여 경량 유사도 함수를 정의한다. 경량 유사도 함수는 유사도 함수에 비해 데이터를 여과하는 정확도는 떨어지지만 비용이 유사도 함수에 비하여 적게 소모되는 특징이 있다. 이러한 경량 유사도 함수의 특징을 이용하여 유사도 질의 처리 비용 감소 방법을 제시한다. 그리고 유클리드 거리 함수에 경량 유사도 함수로 체비쇼프 거리를 제시하고 기존의 유사도 함수를 이용하는 질의와 경량 유사도 함수를 이용하는 질의의 처리 비용을 비교한다. 그리고 실험을 통하여 유클리드 유사도에 대한 경량 유사도 함수로 체비쇼프 거리를 적용하였을 때 유사도 질의 처리 비용이 감소하는 것을 확인한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5692-5716
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• 2019

One of the best means to safeguard the confidentiality, security, and privacy of an image within the IoT-Cloud is through encryption. However, looking through encrypted data is a difficult process. Several techniques for searching encrypted data have been devised, but certain security solutions may not be used in IoT-Cloud because such solutions are not lightweight. We propose a lightweight scheme that can perform a content-based search of encrypted images, namely EEIRI. In this scheme, the images are represented using local features. We develop and validate a secure scheme for measuring the Euclidean distance between two descriptor sets. To improve the search efficiency, we employ the k-means clustering technique to construct a searchable tree-based index. Our index construction process ensures the privacy of the stored data and search requests. When compared with more familiar techniques of searching images over plaintexts, EEIRI is considered to be more efficient, demonstrating a higher search cost of 7% and a decrease in search accuracy of 1.7%. Numerous empirical investigations are carried out in relation to real image collections so as to evidence our work.

• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1117-1126
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• 2013

The standard impact sources, standardized to rate the sound insulation performance of floor structure, should simulate well the real floor impact sources, which is very important to grade the floor structure then to establish counter plan to improve the performance of floor. Recently the tire, the standard heavyweight impact source, has been discussed that the impact force is too big to represent the real impact force. And researches have been carried on the applicability as a substitute or a supplementary. In addition, tapping machine, the standard lightweight impact source, is also questionable if it is representative of real lightweight impact source. This study aims to examine the similarity of standard impact sources with living impact sources, comparing the physical characteristics such as impact force, frequency contents and sound level. The result showed that the physical characteristics of standard impact sounds were somewhat different with that of living impact sounds, and the standard sources couldn't be verified from this result. Later subjective evaluation should be followed to compare how the physical differences make relationship with the subjective differences.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4065-4083
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• 2021

Super-resolution can improve the clarity of low-resolution (LR) images, which can increase the accuracy of high-level compute vision tasks. Portable devices have low computing power and storage performance. Large-scale neural network super-resolution methods are not suitable for portable devices. In order to save the computational cost and the number of parameters, Lightweight image processing method can improve the processing speed of portable devices. Therefore, we propose the Enhanced Information Multiple Distillation Network (EIMDN) to adapt lower delay and cost. The EIMDN takes feedback mechanism as the framework and obtains low level features through high level features. Further, we replace the feature extraction convolution operation in Information Multiple Distillation Block (IMDB), with Ghost module, and propose the Enhanced Information Multiple Distillation Block (EIMDB) to reduce the amount of calculation and the number of parameters. Finally, coordinate attention (CA) is used at the end of IMDB and EIMDB to enhance the important information extraction from Spaces and channels. Experimental results show that our proposed can achieve convergence faster with fewer parameters and computation, compared with other lightweight super-resolution methods. Under the condition of higher peak signal-to-noise ratio (PSNR) and higher structural similarity (SSIM), the performance of network reconstruction image texture and target contour is significantly improved.

• 대한임베디드공학회논문지
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• 제15권5호
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• pp.205-214
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• 2020

With the recent development of hardware and software technology, interest in the development of wearable devices is increasing. In particular, wearable devices require algorithms suitable for low-power and low-capacity embedded devices. Among them, there is an increasing demand for a signal compression algorithm that reduces communication overhead, in order to increase the efficiency of storage and transmission of electrocardiogram (ECG) signals requiring long-time measurement. Because normal beats occupy most of the signal with similar shapes, a high rate of signal compression is possible if normal beats are represented by a template. In this paper, we propose an algorithm for determining the normal beat template using the template cluster and Pearson similarity. Also, the template is expressed effectively as a few vertices through linear approximation algorithm. In experiment of Datum 234 of MIT-BIH arrhythmia database (MIT-BIH ADB) provided by Physionet, a compression ratio was 33.44:1, and an average distribution of root mean square error (RMSE) was 1.55%.

• 한국전자통신학회논문지
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• 제15권5호
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• pp.981-986
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• 2020

사물인터넷은 장소나 시간에 제약 없이 센서와 통신 기능이 내장된 사물이 사람과 사물에 상호 작용이 가능하도록 구성된 사물 공간 연결망을 말한다. IoT는 인간의 편의를 위한 서비스 목적으로 개발된 연결망이지만 현재는 전력전송, 에너지관리, 공장자동화와 같은 산업 전반에 그 사용범위가 확대되고 있는 상태이다. 그러나 IoT의 통신프로토콜인 MQTT는 푸시 기술 기반의 경량 메시지 전송 프로토콜로 보안에 취약함을 갖고 있고 이것은 개인정보 침해나 산업정보 유출 같은 위험성이 내재되어 있다고 할 수 있다. 우리는 이런 문제점을 해결하기 위해 경량 메시지전송 MQTT 프로토콜에 서로 다른 혼돈계가 임의의 값으로 동기화되는 특성을 이용하여 보안 채널을 생성하는 동기화 MQTT 보안 채널을 설계하였다. 우리가 설계한 통신 채널은 혼돈 신호의 난수 유사성, 초기치 민감성, 신호의 재생산성과 같은 특성을 이용한 방법으로 잡음 채널에 정보를 전송하는 방법이라고 할 수 있다. 우리가 제시한 킷값으로 동기화된 암호화 방법은 경량 메시지 전송 프로토콜에 최적화된 방법으로 IoT의 MQTT에 적용된다면 보안 채널 생성에 효과적이라고 할 수 있다.

• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1045-1055
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• 2013

It is true that the dependency on import is currently high in case of the safety checkup system of domestic airplanes, and it is at the point of time that localization of HUMS for small airplanes is required. In this study, the design factors were selected for the lightweight of HUMS for small airplanes by using Pro-Engineer which is a design tool and Abaqus. 9 models were made through experiment plans with Taguchi method for this, and the each model for weight lightening was selected through vibration analysis and shock analysis while in operation with experiment profile values. After fabricating HUMS, it was verified that as a result of experiment with the same profile values as the analysis, there was similarity between the analyzed values and values of the experiment. As a result of performing weight lightening which is the purpose of the study, electronic performance for small airplanes is assured and a design plan reducing 15 % weight compared to the targeted weight was deduced. Besides, it could be verified that the light weight model satisfied the maximum allowable displacement value of PCB[printed circuit board] and accordingly satisfied electronic properties of HUMS. In this study, the reliability of a product was certified through the result of an experiment on ground. If the reliability of HUMS were verified through a test flight in the future, it is considered that it would make a big contribution to localization of aerospace electronic equipment.