• 한국컴퓨터정보학회논문지
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• 제22권3호
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• pp.1-8
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• 2017

In this paper, we propose a new hybrid wear leveling technique for NAND Flash memory, called Time-Aware Wear Leveling (TAWL). Our proposal prolongs the lifetime of NAND Flash memory by using dynamic wear leveling technique which considers the wear level of hot blocks as well as static wear leveling technique which considers the wear level of the whole blocks. TAWL also reduces the overhead of garbage collection by separating hot data and cold data using update frequency rate. We showed that TAWL enhanced the lifetime of NAND flash memory up to 220% compared with previous wear leveling techniques and our technique also reduced the number of copy operations of garbage collections by separating hot and cold data up to 45%.

• Journal of Information Technology Applications and Management
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• 제14권4호
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• pp.31-41
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• 2007

In order to keep global competitiveness, most of small and medium size manufacturing companies require to equip a product information management system which collects and analyzes the data generated at the manufacturing lines and then provides information for manager or worker to make a decision. However, these companies have a cost problem for adopting the enterprise resource planning system mostly used in large companies. To overcome this problem, we suggest an IOCP-based server for the product information management system suitable for small and medium size manufacturing companies. The basic concept of suggested server is that it is possible to process concurrently the connection requests coming from data collector and client by using the facility of asynchronous notification of OS and protect a server against overload by using the thread pool.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.229-240
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• 2012

Advances in MEMS and CMOS technologies have motivated the development of low cost/power sensors and wireless multimedia sensor networks (WMSN). The WMSNs were created to ubiquitously harvest multimedia content. Such networks have allowed researchers and engineers to glimpse at new Machine-to-Machine (M2M) Systems, such as remote monitoring of biosignals for telemedicine networks. These systems require the acquisition of a large number of data streams that are simultaneously generated by multiple distributed devices. This paradigm of data generation and transmission is known as event-streaming. In order to be useful to the application, the collected data requires a preprocessing called data fusion, which entails the temporal alignment task of multimedia data. A practical way to perform this task is in a centralized manner, assuming that the network nodes only function as collector entities. However, by following this scheme, a considerable amount of redundant information is transmitted to the central entity. To decrease such redundancy, data fusion must be performed in a collaborative way. In this paper, we propose a collaborative data alignment approach for event-streaming. Our approach identifies temporal relationships by translating temporal dependencies based on a timeline to causal dependencies of the media involved.

• Journal of Information Processing Systems
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• 제17권5호
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• pp.989-1003
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• 2021

With the recent increase in the types of services provided by Internet companies, collection of various types of data has become a necessity. Data collectors corresponding to web services profit by collecting users' data indiscriminately and providing it to the associated services. However, the data provider remains unaware of the manner in which the data are collected and used. Furthermore, the data collector of a web service consumes web resources by generating a large amount of web traffic. This traffic can damage servers by causing service outages. In this study, we propose a website search engine that employs a system that controls user information using blockchains and builds its database based on the recorded information. The system is divided into three parts: a collection section that uses proxy, a management section that uses blockchains, and a search engine that uses a built-in database. This structure allows data sovereigns to manage their data more transparently. Search engines that use blockchains do not use internet bots, and instead use the data generated by user behavior. This avoids generation of traffic from internet bots and can, thereby, contribute to creating a better web ecosystem.

• 정보보호학회논문지
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• 제18권6A호
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• pp.139-149
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• 2008

조직이나 기관에서 수집한 개인정보를 통계 분석, 공공 의료 연구 등을 목적으로 배포할 때는 데이터에 포함된 개인의 민감한 정보가 노출되지 않도록 보호해야 한다. 한편, 배포되는 데이터는 가능한 정확한 통계 정보를 제공해야 한다. k-anonymity와 l-diversity 모델은 이러한 프라이버시 침해 문제 해결을 위해 제안되었다. 그러나 두 모델은 데이터에 삽입과 삭제가 발생하지 않는 정적인 데이터를 단 한번 배포하는 상황을 가정하기 때문에 삽입과 삭제가 발생하는 동적인 데이터에 그대로 적용할 수 없다. 동적인 데이터의 프라이버시 보호 문제를 해결하기 위해 최근 m-invariance 모델이 제안되었다. 그러나 m-invariant 일반화 기법은 일반화로 인해 통계 정보로써 데이터의 품질을 저하시킨다는 단점이 있고, 배포된 데이터 중 일부 개인의 민감한 속성이 노출되었을 경우에 그 영향이 다른 부분으로 전이된다. 본 논문에서는 일반화를 사용하지 않으면서 간단한 삽입과 삭제 연산을 지원하는 동적 데이터의 배포 기법을 제안한다. 제안 기법은 데이터의 품질을 높이면서 m-invariance와 동등한 수준의 프라이버시 보호 정도를 제공한다.

• 한국정보통신학회논문지
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• 제17권9호
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• pp.2097-2104
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• 2013

과학기술연구의 데이터가 기하급수적으로 증가함에 따라 대용량 데이터 처리를 위한 컴퓨팅 및 저장장비의 필요에 따라 한국과학기술정보연구원(KISTI: Korea Institute of Science and Technology Information)은 글로벌 대용량 실험데이터 허브센터(GSDC: Global Science experimental Data hub Center)를 구축하여 지원하고 있다. KISTI는 급격히 확산되고 있는 모바일 기기에서 이용이 가능한 GSDC의 글로벌 커뮤니티 및 서비스를 위해 모바일 웹 표준으로 Mobile User Portal Service(MUPS)를 구축하였다. 그리고 이러한 MUPS에서 GSDC의 운영상태 및 시스템 자원 분석을 위해, 본 논문에서는 모바일 웹 환경에서 GSDC의 시스템 자원 모니터링 방법을 연구하고 구현하였다. GSDC의 연구지원 시스템은 Scientific Linux로 운영되고 있고, Sysstat 자원 감시 도구를 통해 sadc(system activity data collector)로 시스템자원 활용 정보를 모은 후 sar(System Analysis Report)를 통해 리포트를 매일 작성한다. 본 논문에서는 이러한 sar 리포트를 모바일 환경에서 시각화하여 활용이 가능하도록 모바일 웹으로 설계하고 구현하였다. 모바일 웹으로 구현함으로써 특정 OS에 종속되지 않은 다양한 모바일 OS에서 사용이 가능하고, 기존의 모니터링보다 쉽고 간편하게 시스템 모니터링이 가능하다.

• 설비공학논문집
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• 제16권6호
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• pp.556-565
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• 2004

We have experimented an actual solar water heating system acquiring real data for one year period. On the basis of the operation data, it is necessary to predict the system performance such as collector efficiency and solar fraction, and to analyze the economical efficiency for system optimal design. To estimate the performance of actual systems through simulation, valid modelling for components consisting of the system should be accompanied. The present study is focused on the modelling for load patterns and operating control conditions. We proposed two load models: concentration model which gathers real loads as a meaningful group and distribution model which disperses real loads with time. If grouping of the load distribution is suitable, the predicted values by the concentration model approaches to those by the distribution model close to actual load pattern apparently. As a result, both of them are in good agreement with those by experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.470-472
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• 2006

Sensor networks are the results of convergence of very important technologies such as wireless communication and micro electromechanical systems. In recent years, sensor networks found a wide applicability in various fields such as environment and health, industry scene system monitoring, etc. A very important step for these many applications is pattern classification and recognition of data collected by sensors installed or deployed in different ways. But, pattern classification and recognition are sometimes difficult to perform. Systematic approach to pattern classification based on modem learning techniques like Multivariate Gaussian mixture models, can greatly simplify the process of developing and implementing real-time classification models. This paper proposes a new recognition system which is hierarchically composed of many sensor nodes having the capability of simple processing and wireless communication. The proposed system is able to perform context classification of sensed data using the Multivariate Gaussian function. In order to verify the usefulness of the proposed system, it was applied to intelligent dust collecting system.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2019년도 제60차 하계학술대회논문집 27권2호
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• pp.139-140
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• 2019

난독증은 정상적인 지능에도 불구하고 문장을 읽기가 어려운 독서 장애다. 난독증 진단 방법은 ADHD처럼 증상 체크리스트가 없다. 지적장애를 판정할 때 사용하는 웩슬러 지능검사 같은 전 세계인이 사용하는 아주 보편화된 심리검사도 없다. 미국 진단기준의 최신판인 DSM-5에도 어떤 검사를 해서 기준점수 아래여야 진단할 수 있다고 명확히 써놓지 않았다. 본 논문에서는 이를 해결하기 위해 글자, 단어, 문장, 문단의 단위를 설정하여 화면에 출력하고 아이트래커를 활용하여 읽는 사람의 시선 데이터를 수집하여 히트맵으로 분석한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.436-438
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• 2007

As the sensors and communication technology get advance, the remote health diagnosis for patients and senior persons at home are possible now without visiting doctors in hospitals. A low-power ubiquitous health check device was developed adapting Real-Time Embedded Linux is developed. This ubiquitous device is consisted of three sensors. The wrist type health checking terminal acquires periodically the health data by using a blood pressure sensor, a pulse sensor and a body temperature sensor. It transmits the health data to the access point located at the home center through the ZigBee wireless communication modem. This health data collector or access point device sends the data again to the main server operated in a hospital or health care organization. The health server control continuously the input data and sends an alarm signal to the assigned. doctor and responsible persons using cellular SMS when any dangerous events occur. This wrist type health check device has an embedded linux OS using Intel PAX255 MPU. The developed U-Health system is applicable for checking patients health in remote at home. And their family or related persons in remote site can check the patients health status at any time. They can be assured by receiving SMS record and alarm of emergency case which is transmitted from the health server.