• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.2
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• pp.7-30
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• 1998

Generation and recycling potential of organic waste in Korea were estimated. Status of organic waste composting and compost utilization also were surveyed to promote the recycling of organic waste. From 1994 to 1997, generation of garbage decreased gradually while recycling rate increased due to positive governmental strategy. During the same period, livestock waste increased 11.2%. Municipal wastewater sludge was generated 3,500 ton/day which was 0.03% of wastewater treated in 1996. The energy Potential of industrial organic waste was estimated to 288 million TOE which was 1.75% of the nationwide first energy consumption in 1996. Recycling of industrial sludge was low to 31%, while recycling of animal waste, plant scraps, and wasted paper were relatively high over 50%. Industrial sludge should be recycled more as it was the most part of industrial organic waste. Conventional composting materials were mainly livestock waste, food processing waste, fishery waste, sawdust, and nightsoil. Garbage and sludge have been composted recently. 420,000 tons of compost in 1996 were produced by 288 makers, the most of which were utilized in agriculture. It was suggested that separated collection, compost standard, and quality management should be provided to promote the composting of organic waste.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.86-94
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• 2004

The characteristics of food waste in our country is high contents of water and sodium chloride(NaCl). Average water contents of household garbage was 80.0%, and those of wastes of restaurants and of wholesale market of agricultural products was 76.9% and 90.0%, respectively. The NaCl contents were high in household garbage and restaurant's waste as 3.36% and 4.84%, respectively. The NaCl contents of food waste composts made by various techniques known upto now were under the level of 1% by fresh weight basis. But these techniques has some problem that is environment pollution from treated water and high equipment cost. The application to agricultural land of food waste compost that is not sufficiently removed NaCl was considered to be improper due to salt accumulation in soils and plant growth inhibition by salt stress. The purpose of this study is to decompose NaCl in food waste compost using triple salt and this method is differ from existing chemical method. Also, reaction of NaCl with triple salt produced KCl that is basic material of potassium fertilizer. The experiment results of growing lettuce produced difference between food waste compost and treated food waste compost with triple salt. The latter got more high sprouting ratio and a growth rate.

• Resources Recycling
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• v.23 no.5
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• pp.44-54
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• 2014

A standard plastic garbage bag which was discarded from Incheon Metropolitan City was composed of 4.5% recyclable resources (aluminum cans 0.2%, steel cans 2.5%, glass 1.8%), 92.5% resources with recoverable energy (papers 23.0%, plastics 15.5%, combustible etc. 54.0%) and 3.0% non-combustible etc. Recycling is more effective than landfilling for aluminum cans, steel cans, and glass. The energy recovery process using solid refuse fuel (SRF) is more effective than incineration for papers and plastics. Incineration is more effective than recycling for combustible etc. 2,068,948 Million Btu of total energy savings and 21,008 $MTCO_2E$ of total GHG reductions were obtained by the application of the proposed scheme. The total energy savings were equivalent to an economic benefit of 422 billion won per year. The total GHG reductions were equivalent to a GHG benefit of 4,119 passenger cars not running per year. The lower calorific value of the combustible materials was obtained to be 1,936 kcal/kg of papers, 5,079 kcal/kg of plastics and 2,462 kcal/kg of combustible other resources, respectively. If papers and plastics are properly mixed, the mixture can be used as SRF. The lower calorific value of combustible other resources does not meet the quality criteria for refuse derived fuel, therefore its components are inappropriate to used as solid refuse fuel.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.123-129
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• 2012

Recently, interests on cleaning robots workable in pipes (termed as in-pipe cleaning robot) are increasing because Garbage Automatic Collection Facilities (i.e, GACF) are widely being installed in Seoul metropolitan area of Korea. So far research on in-pipe robot has been focused on inspection rather than cleaning. In GACF, when garbage is moving, the impurities which are stuck to the inner face of the pipe are removed (diameter: 300 mm or 400 mm). Thus, in this paper, by using TRIZ (Inventive Theory of Problem Solving in Russian abbreviation), an in-pipe cleaning robot of GACF with the 6-link sliding mechanism will be proposed, which can be adjusted to fit into the inner face of pipe using pneumatic pressure(not spring). The proposed in-pipe cleaning robot for GACF can have forward/backward movement itself as well as rotation of brush in cleaning. The robot body should have the limited size suitable for the smaller pipe with diameter of 300 mm. In addition, for the pipe with diameter of 400 mm, the links of robot should stretch to fit into the diameter of the pipe by using the sliding mechanism. Based on the conceptual design using TRIZ, we will set up the initial design of the robot in collaboration with a field engineer of Robot Valley, Inc. in Korea. For the optimal design of in-pipe cleaning robot, the maximum impulsive force of collision between the robot and the inner face of pipe is simulated by using RecurDyn(R) when the link of sliding mechanism is stretched to fit into the 400 mm diameter of the pipe. The stresses exerted on the 6 links of sliding mechanism by the maximum impulsive force will be simulated by using ANSYS$^{(R)}$ Workbench based on the Design Of Experiment(in short DOE). Finally the optimal dimensions including thicknesses of 4 links will be decided in order to have the best safety factor as 2 in this paper as well as having the minimum mass of 4 links. It will be verified that the optimal design of 4 links has the best safety factor close to 2 as well as having the minimum mass of 4 links, compared with the initial design performed by the expert of Robot Valley, Inc. In addition, the prototype of in-pipe cleaning robot will be stated with further research.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1167-1175
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• 2016

This paper proposes an efficient page-level mapping algorithm that reduces the erase count in the FTL for flash memory systems. By maintaining the weight for each write request in the request buffer, the proposed algorithm estimates the degree of temporal locality for each incoming write request. To exploit temporal locality deliberately for determination of hot request, the degree of temporal locality should be much higher than the reference point determined experimentally. While previous LRU algorithm treats a new write request to have high temporal locality, the proposed algorithm allows write requests that are estimated to have high temporal locality to access hot blocks to store hot data intensively. The pages are more frequently updated in hot blocks than warm blocks. A hot block that has most of invalid pages is always selected as victim block at Garbage Collection, which results in delayed erase operation and in reduced erase count. Experimental results show that erase count is reduced by 9.3% for real I/O workloads, when compared to the previous LRU algorithm.

• The Journal of Bigdata
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• v.6 no.1
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• pp.179-196
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• 2021

With the spread of untact culture resulting from the Covid-19 pandemic, the size of the car camping market has expanded to minimize contact with others. As a result, SUVs have exceeded sales of sedans, and sales of recreational vehicles (RVs) have increased by 101% compared to the same period last year. Despite the explosive increase in demand for car camping, research on car camping has not matched this increase. Therefore, in this study, we intended to conduct a study focused on car camping users. According to a survey of Naver's famous car camping cafe, it was difficult to find articles, maps, and websites with car camping places. Analysis of car camping websites showed that most only post information about the camping itself, so details of car camping places were not available. Furthermore, according to a survey derived from related prior studies and literature surveys, most users urged solutions to the problem of unauthorized garbage dumping in the car camping locations. In addition, car camping users wanted to receive information on amenities near the car camping places. Therefore, we aimed to establish a car camping website that provides basic information on car camping places and nearby convenience facilities. Moreover, to solve the problem of garbage dumping, we provided a category wherein users can post pictures of clean camping campaigns. We also developed a business model utilizing the certification process of clean camping. The business model is designed with a structure wherein car camping users are rewarded through the clean camping certification process. Compensation for clean camping certification was proposed to be provided through partnerships with domestic automakers, Korea Tourism Organization, and Small Business Market Promotion Agency.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.10a
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• pp.355-361
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• 1999

An application of case-based reasoning is proposed to build an influence diagram for identifying successful new ventures. The decision to invest in new ventures in characterized by incomplete information and uncertainty, where some measures of firm performance are quantitative, while some others are substituted by qualitative indicators. Influence diagrams are used as a model for representing investment decision problems based on incomplete and uncertain information from a variety of sources. The building of influence diagrams needs much time and efforts and the resulting model such as a decision model is applicable to only one specific problem. However, some prior knowledge from the experience to build decision model can be utilized to resolve other similar decision problems. The basic idea of case-based reasoning is that humans reuse the problem solving experience to solve a new decision. In this paper, we suggest a case-based reasoning approach to build an influence diagram for the class of investment decision problems. This is composed of a retrieval procedure and an adaptation procedure. The retrieval procedure use two suggested measures, the fitting ratio and the garbage ratio. An adaptation procedure is based on a decision-analytic knowledge and decision participants knowledge. Each step of procedure is explained step by step, and it is applied to the investment decision problem in new ventures.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1764-1773
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• 2011

This study is about how to handle very soft grounds consisted of coal and household garbage(organic soil), clay, silt and so on, through examining Seoul-Busan High-Speed railway 6-2nd section. The soft soil might induce long term settlement and lead to structure's differential settlement eventually. So, we performed the boring test for characteristic of railway ground, laboratory test and field survey for mechanical property. And we also collected the engineering data of ground and the data for the establishment arrangement. These data were examined thoroughly considering residual settlement and strength by high-speed railway design standard. As a result of this study, we can say high-speed railway ground must have enough bearing capacity and be settled under allowable residual settlement(10cm). And also it needs to replace soft ground with high quality sand for the fundamental solution. With the application of replacement method on this study, we expect enough condition to construct stable high-speed railway.

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.321-330
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• 2008

Methane is a potent greenhouse gas and methane emissions from landfills have been linked to global warming. In this study, LandGEM (Landfill Gas Emission Model) was applied to predict landfill gas quantity over time, and then this result was compared with the data surveyed on the site, Cheongju Megalo Landfill. LandGEM allows the input of site-specific values for methane generation rate (k) and potential methane generation capacity $L_o$, but in this study, k value of 0.05/yr and $L_o$ value of $170m^3/Mg$ were considered to be most appropriate for reflecting non-arid temperate region conventional landfilling, Cheongju Megalo Landfill. High discrepancies between the surveyed data and the predicted data about landfill gas seems to be derived from insufficient compaction of daily soil-cover, inefficient recovery of landfill gas and banning of direct landfilling of food garbage waste in 2005. This study can be used for dissemination of information and increasing awareness about the benefits of recovering and utilizing LFG (landfill gas) and mitigating greenhouse gas emissions.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.1
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• pp.9-16
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• 2020

Recently, the capacity of SSD has been increasing rapidly due to the improvement of flash memory density. To take full advantage of these SSDs, first of all, FTL's prompt adaptation is necessary. The FTL is a translation layer existing in SSDs to overcome the drawback of the SSD that cannot be modified in place, and has garbage collection and caching functions in addition to the map table management function. In this study, we focus on caching function, compare and analyze the cache implementation methodologies, and propose improved methods. Typical cache implementations divide the cache into groups, manage and retrieve the caches in the group as a linked list. Thus, searches are made in the order of the linked list. In contrast, we propose a method of sequential searching using the search area group of a cache registered in the map table regardless of the linked list and cache group. Experimental results show that the proposed method has a 2.5 times improvement over the conventional method.