• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제7권1호
• /
• pp.7-14
• /
• 2003

The main concern of this paper is to develop a new class of quasi-newton methods. These methods are intended for use whenever memory space is a major concern and, hence, they are usually referred to as limited memory methods. The methods developed in this work are sensitive to the choice of the memory parameter ${\eta}$ that defines the amount of past information stored within the Hessian (or its inverse) approximation, at each iteration. The results of the numerical experiments made, compared to different choices of these parameters, indicate that these methods improve the performance of limited memory quasi-Newton methods.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제34권6호
• /
• pp.562-571
• /
• 2007

많은 연구들을 통해 수행 속력, 효율성, 용이성, 안전성을 위하여 메모리 관리 기법들을 개선시켰다. 그러한 방법들 중에서 지역별 메모리 관리 기법은 각각의 객체 할당 위치에서 따라 정해진 지역에 할당 시키고 그 지역이 제거된다면 그 곳에 할당된 모든 객체의 메모리를 반환하는 방법이다. 본 논문에서는 메모리 제약적인 환경에서 힙 메모리 사용량을 줄이기 위해 로컬 지역을 재사용하는 방법을 제시한다. 기본 아이디어는 현재 함수가 수행될 동안 사용하지 않는 상위 로컬 지역을 재사용하는 것이다. 이러한 방법을 사용함으로써 메모리 제약적인 환경에서 메모리의 한계를 극복할 수 있을 것이다.

• 한국컴퓨터정보학회논문지
• /
• 제20권11호
• /
• pp.1-8
• /
• 2015

Flash memory has advantages in that it is fast access speed, low-power, and low-price. Therefore, they are widely used in electronics industry sectors. However, the flash memory has weak points, which are the limited number of erase operations and non-in-place update problem. To overcome the limited number of erase operations, many wear leveling techniques are studied. They use many tables storing information such as erase count of blocks, hot and cold block indicators, reference count of pages, and so on. These tables occupy some space of main memory for the wear leveling techniques. Accordingly, they are not appropriate for low-power devices limited main memory. In order to resolve it, a wear leveling technique using bit array and Bit Set Threshold (BST) for flash memory. The proposing technique reduces the used space of main memory using a bit array table, which saves the history of block erase operations. To enhance accuracy of cold block information, we use BST, which is calculated by using the number of invalid pages of the blocks in a one-to-many mode, where one bit is related to many blocks. The performance results illustrate that the proposed wear leveling technique improve life time of flash memory to about 6%, compared with previous wear leveling techniques using a bit array table in our experiment.

• 대한수학회지
• /
• 제47권4호
• /
• pp.767-788
• /
• 2010

In this paper, we propose two limited memory BFGS algorithms with a nonmonotone line search technique for unconstrained optimization problems. The global convergence of the given methods will be established under suitable conditions. Numerical results show that the presented algorithms are more competitive than the normal BFGS method.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권9호
• /
• pp.3396-3411
• /
• 2015

Sensors used in Wireless Sensor Networks (WSN) have mostly limited capacity which affects the performance of their applications. One of the data-gathering methods is to use mobile sinks to visit these sensors so that they can save their limited battery energies from forwarding data packages to static sinks. The main disadvantage of employing mobile sinks is the delay of data collection due to relative low speed of mobile sinks. Since sensors have very limited memory capacities, whenever a mobile sink is too late to visit a sensor, that sensor's memory would be full, which is called a 'memory overflow', and thus, needs to be purged, which causes loss of collected data. In this work, a method is proposed to generate mobile sink tours, such that the number of overflows and the amount of lost data are minimized. Moreover, the proposed method does not need either the sensor locations or sensor memory status in advance. Hence, the overhead stemmed from the information exchange of these requirements are avoided. The proposed method is compared with a previously published heuristic. The simulation experiment results show the success of the proposed method over the rival heuristic with respect to the considered metrics under various parameters.

• Journal of Information Technology Applications and Management
• /
• 제11권1호
• /
• pp.189-200
• /
• 2004

Recently Flash Memory which is small and low-powered is widely used as a storage of embedded system, because an embedded system requests portability and a fast response. To resolve a difference of access time between a storage and RAM, Linux is using disk caching which copies a part of file on disk into RAM. It is not also an exception on embedded system. A READ access-time of flash memory is similar to RAMs. So, when a process on an embedded system reads data, it is similar to the time to access cached data in RAM and to access directly data on a flash memory. On the embedded system using limited memory, using a disk cache is that wastes much time and memory spaces to manage it and can not reflects the characteristic of a flash memory. This paper proposes the regular file access of limited using a page cache in the file system based on a flash memory and reflects the characteristic of a flash memory. The proposed algorithm minimizes power consumption because access numbers of the RAM are reduced and doesn't waste a memory space because it accesses directly to a flash memory Therefore, the performance improvement of the system applying the proposed algorithm is expected.

• ETRI Journal
• /
• 제30권3호
• /
• pp.483-485
• /
• 2008

A micro-sensor network is comprised of a large number of small sensors with limited memory capacity. Current key-establishment schemes for symmetric encryption require too much memory for micro-sensor networks on a large scale. In this paper, we propose a memory-efficient hypercube key establishment scheme that only requires logarithmic memory overhead.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
• /
• pp.97-101
• /
• 1986

This paper deals with the problem of stability and error analyses of the FIR filter and the limited memory filters. It is shown that the FIR filter has the best performance among them, which is demonstrated by some simple examples and via simulations.

• 한국정보처리학회논문지
• /
• 제6권4호
• /
• pp.1098-1105
• /
• 1999

분산 공유 메모리(distributed shared memory) 시스템에서 캐쉬는 메모리 접근 지연과 통신 부하 줄임으로 성능을 향상시킬 수 있으나 캐쉬일관성 문제를 해결하여야 한다. 본 논문은 DSM 시스템에서 캐쉬일관성 문제를 해결하고 성능을 향상시킬 수 있는 새 디렉터리 프로토콜을 제안한다. 캐시 일관성을 유지하기 일정거리 이내에 있는 처리기는 전체 디렉터리 기법처럼 비트 벡터를 사용하여 통신 오버헤드를 줄일 수 있다. 그리고 일정거리 이상에 있는 처리기는 포인터를 디렉터리 풀에 저장한다. 이 비트 벡터와 디렉터리 풀의 사용은 불필요한 캐쉬 무효화를 방지하므로 시스템의 성능을 향상시킬 수 있다. 제안한 기법은 제한 디렉터리 기법보다 통행량을 66%까지 줄일 수 있으며 동적할당 디렉터리 기법보다 디렉터리 접근 회수도 27%까지 각각 줄일 수 있다.

• 한국시뮬레이션학회논문지
• /
• 제12권4호
• /
• pp.95-102
• /
• 2003

Stream servers are for supplying multimedia stream data to users through the internet such as movies and music without discontinuation. A typical stream server is designed roughly by considering the characteristics of stream services and by employing processors, memory, PCI bus, Ethernet, TOE and disks. This study focuses on deciding the priority for using resources such as PCI bus, buffer memory and TOE buffer, which have limited capacities in a typical stream server. When the priorities for using limited resources are not given properly, the stream servers may not even function as originally designed. The simulation study shows that the top priority for using PCI bus for normal streaming services should be given to the operation that sends data from buffer memory to TOE buffer. Giving priority for using PCI bus to other operation such as sending data from disks to memory results in a deadlock phenomenon.