• Journal of KIISE:Computer Systems and Theory
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• v.29 no.6
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• pp.331-339
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• 2002

This paper presents a garbage collection protocol for checkpoints and message logs which are staved on the stable storage or volatile storage for fault tolerancy. The previous works of garbage collections in coordinated checkpointing protocol delete all the checkpoints except for the last checkpoints on earth processes. But implemented in top of reliable communication protocol like as TCP/IP, rollback recovery protocol based on only last checkpoints makes sympathetic rollback. We show that the old checkpoints or message logs except for the last checkpoints have to be preserved in order to replay the lost message. And we define the conditions for garbage collection of checkpoints and message logs for lost messages and present the garbage collection algorithm for checkpoints and message logs in coordinated checkpointing protocol. Since the proposed algorithm uses process information for lost message piggybacked with messages, the additional messages for garbage collection is not required The proposed garbage collection algorithm makes 'the lazy garbage collectioneffect', because relying on the piggybacked checked checkpoint information in send/receive message. But 'the lazy garbage collection effect'does not break the consistency of the whole systems.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.3 s.309
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• pp.20-29
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• 2006

The Java language has been established as one of the most widely used language due to its object-oriented programming, safety and flexibility and the garbage collection of the virtual machine has relieved programmers of many difficulties related to the memory management. In the embedded environment, Java is also prevalent, the virtual machine and garbage collector that takes into account the embedded environment is required. In this paper we manage the heap memory area by dividing into young generation and old generation, and we propose a garbage collector in which appropriate techniques are applied to each generation to utilize the different characteristics of each generation. Also, we propose the write barrier technique and double filtering technique for efficient garbage recognition, and double check method for determining and reclaiming the garbage with cyclic structure. The proposed method satisfies the embedded environment's requirements of fast object allocation, real time property, recollection of all the garbage, elimination of fragmentations and high locality.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.441-450
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• 2002

As the size of embedded system software increase bigger and bigger, and it's complexity is grower and grower, the usage of dynamic memory management scheme such collector also has been increased. Using the garbage collector, however, inherently lead us performance degradation. In order to resolve this kind of performance problem in the Java based embedded system. we introduce an explicit dynamic memory free method to the automated dynamic memory management environment. which can be performed by a programmer. In the worst case, the prosed scheme shows the same performance as the case of that only garbage collector is working, since the unclaimed garbage objects will eventually be collected later by the garbage collector. In the best case. our method is free from any runtime overhead because the applications can be implemented without any intervention of the garbage collector. Although the proposed method can be facilitated with all the existing garbage collection algorithms, it shows an outperform in the case of mark-and-sweep algorithm.

• Hwankyungkyoyuk
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• v.11 no.1
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• pp.151-164
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• 1998

Conclusion and the improvement plan according to the survey on recycling wastes in 'the program of woman and environmental education' mainly for the chairwomen of the women's association of the apartment house in City and County of Chungchongnamdo during the first half of 1998 (from March tp April) are as follows. 1. Conclusion 1) It showed that the rate of recognition for recycle has no difference by regional groups and the rate of recognition is 57.4% but they mainly know vaguely or they do not know. 2) It showed that the rate they do not know how the separated wastes are recycled is 30.4% and the scope of their knowledge is approximative.(52.6%) 3) It showed that it is the housewives who mainly do the separate garbage collection (72.7%) and 19.1% of the people have no interest in the separate discharge. 4) It showed that the rate they filter the garbage or remove water from the garbage at house is 53.1%. And 20% of the people in the urban region dump untreated wastes but 8.5% of the people in the rural region do the same, so the rate of using garbage in the rural region is higher than that in the urban region. 5) It showed that the separate state of the garbage is 29.2% for the removal of toothpick and paper and 47.4% for the removal of vinyl and stopper. 6) It showed that 66.7% of the motive for recycling waste is the education activity for environment by the women's association and SAEMAEUL association and 34.5% of that is the influence of TV and radio. 7) It showed that the rate of making compost and feed using garbage in the rural region is higher than that in the urban region and in some urban regions, the rate they sprinkle the garbage in provisional compost state on the floor garden is high. 8) It showed that the recognition rate for the material of separately collected garbage corresponding to the separate waste system of 5-6 classification is 12.5% 9) It showed that the major variable which has an effect on the recycle is the education activity for environment by the neighborhood meeting(P<0.05) and by the women's association of saemaeul activity(P<0.05)

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.793-795
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• 2005

플래시 메모리는 PDA 등과 같은 모바일 장치에 많이 사용되는 저장 매체이다. 이 매체는 덮어 쓰기가 불가능하다는 특징으로 인해 흔히 JFFS2와 같은 전용 파일 시스템을 사용하게 된다. 현재의 JFFS2 파일 시스템은 Garbage Collection 시 많은 자원과 시간을 소비하는 문제점을 가지고 있다. 본 논문에서는 JFFS2 Garbage Collector에서 유효한 노드에 대한 다시 쓰기 작업을 개선한 새로운 Garbage Collector를 설계하였고, 이에 대한 성능 평가를 수행하였다.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.57-61
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• 2009

Garbage cause an environmental pollution, unsightly mess, fouls an odor, and unpleasant feeling. Various measures to solve the problems are studying. And the garbage are collected and treated by the street cleaner. Street cleaner is working for long time in the street from dawn to the night. And many kind of accidents are aroused, like traffic and crushing accident by garbage truck. This kind of accidents is increased every year. To prevent the accident, street cleaner wear a fluorescent light uniform But a count measures for the fallen accident and crushing accident from the garbage truck are insufficient. In addition, a street cleaner dose not like to wear a working uniform because of inconvenience. Therefore this study try to find a safety system of garbage truck for reducing measure of accidents of street cleaner.

• Journal of Korea Multimedia Society
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• v.24 no.11
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• pp.1508-1517
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• 2021

In CCTV environments, a lot of learning image data is required to monitor illegal dumping of garbage with a typical image-based object detection using deep learning method. In this paper, we propose a system to monitor unauthorized dumping of garbage by learning the articular points of the person using only a small number of images without immediate use of the image for deep learning. In experiment, the proposed system showed 74.97% of garbage dumping detection performance with only a relatively small amount of image data in CCTV environments.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.1-9
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• 2019

This paper presents three potential risks in an environment that simultaneously performs the garbage collection and wear leveling in NAND flash memory. These risks may not only disturb the lifespan improvement of NAND flash memory, but also impose an additional overhead of page migrations. In this paper, we analyze the interference of garbage collection and wear leveling and we also provide two theoretical considerations for lifespan prolongation of NAND flash memory. To prove two solutions of three risks, we construct a simulation, based on DiskSim 4.0 and confirm realistic impacts of three risks in NAND flash memory. In experimental results, we found negative impacts of three risks and confirmed the necessity for a coordinator module between garbage collection and wear leveling for reducing the overhead and prolonging the lifespan of NAND flash memory.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1710-1717
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• 2009

Flash memory has become the most important storage media in mobile devices along with its attractive features such as low power consumption, small size, light weight, and shock resistance. However, a flash memory can not be written before erased because of its erase-before-write characteristic, which lead to some garbage collection when there is not enough space to use. In this paper, we propose a novel garbage collection scheme, called block-level buffer garbage collection. When it is need to do merge operation during garbage collection, the proposed scheme does not merge the data block and corresponding log block but also search the block-level buffer to find the corresponding block which will be written to flash memory in the next future, and then decide whether merge it in advance or not. Our experimental results show that the proposed technique improves the flash performance up to 4.6% by reducing the unnecessary block erase numbers and page copy numbers.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.1-11
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• 2015

Recently, NAND flash memories are used for storage devices because of fast access speed and low-power. However, applications of FTL on low power computing devices lead to heavy workloads which result in a memory requirement and an implementation overhead. Consequently, studies of B+-Tree on embedded devices without the FTL have been proposed. The studies of B+-Tree are optimized for performance of inserting and updating records, considering to disadvantages of the NAND flash memory that it can not support in-place update. However, if a general garbage collection method is applied to the previous studies of B+-Tree, a performance of the B+-Tree is reduced, because it generates a rearrangement of the B+-Tree by changing of page positions on the NAND flash memory. Therefor, we propose a novel garbage collection method which can apply to the B+-Tree based on the NAND flash memory without the FTL. The proposed garbage collection method does not generate a rearrangement of the B+-Tree by using a block information table and a proxy block. We implemented the B+-Tree and ${\mu}$-Tree with the proposed garbage collection on physical devices with the NAND flash memory. In experiment results, the proposed garbage collection scheme compared to greedy algorithm garbage collection scheme increased the number of inserted keys by up to about 73% on B+-Tree and decreased elapsed time of garbage collection by up to about 39% on ${\mu}$-Tree.