• 한국산업융합학회 논문집
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• 제23권2_2호
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• pp.351-359
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• 2020

The algae biomass is considered as one of the potential sources of ocean renewable energy because it can be easily mass-produced with abundant sunshine in the vast ocean space. However, the practical use of the biomass has been hindered by the lack of efficient and cost-effective harvesting and maintenance system so far. The algae biomass aquaculture systems are installed in far offshore locations in much larger scales compared to the conventional aquaculture systems so that the automatic seaweed planting and harvesting system needs to operate in heavy sea conditions in far offshore location. In this research, we develop a concept design of a mega-scaled aquaculture system and an automatic seaweed planting and harvesting system, which can operate in heavy seas and mass-produce the algae biomass.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권9호
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• pp.4220-4241
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• 2017

For the downlink energy-harvesting small cell network, this paper proposes an interference management algorithm based on distributed coalitional game. The cooperative interference management problem of the energy-harvesting small cells is modeled as a coalitional game with transfer utility. Based on the energy harvesting strategy of the small cells, the time sharing mode of the small cells in the same coalition is determined, and an optimization model is constructed to maximize the total system rate of the energy-harvesting small cells. Using the distributed algorithm for coalition formation proposed in this paper, the stable coalition structure, optimal time sharing strategy and optimal power distribution are found to maximize the total utility of the small cell system. The performance of the proposed algorithm is discussed and analyzed finally, and it is proved that this algorithm can converge to a stable coalition structure with reasonable complexity. The simulations show that the total system rate of the proposed algorithm is superior to that of the non-cooperative algorithm in the case of dense deployment of small cells, and the proposed algorithm can converge quickly.

• Journal of Forest and Environmental Science
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• 제33권2호
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• pp.147-153
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• 2017

The purpose of this study was to examine productivity and cost of tree-length harvesting using cable yarding system in a larch (Larix leptolepis) clear-cutting stand located in Pyeongchang-gun, Gangwon-do. We used tree-length harvesting method using cable yarding system with a tower yarder HAM300. The productivity was $17.6m^3/hr$ for felling, $12.4m^3/hr$ for delimbing, $4.2m^3/hr$ for yarding, and $8.1m^3/hr$ for processing. The total cost of the harvesting system was $48,381won/m^3$, which was majorly composed of yarding operation cost, at $40,169won/m^3$ (79.3%), while felling had the lowest cost at $1,154won/m^3$ (4.1%). Major factors affecting felling and processing productivity was tree volume and the number and thickness of branches for delimbing productivity. In addition, we suggest that training and education for machine operators were critical to improve yarding productivity.

• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.359-364
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• 2012

Harvesting energy from the environment is essential for many applications to slow down the deterioration of energy of the devices in sensor networks and in general, the network itself. Energy from the environment is an inexhaustible supply which, if properly managed and harvested from the sources, can allow the system to last for a longer period - more than the expected lifetime at the time of deployment, or even last indefinitely. The goal of this study is to develop a simple algorithm for ns-2 to simulate energy harvesting in wireless sensor network simulations. The algorithm is implemented in the energy module of the simulator. Energy harvesting algorithms have not yet been developed for ns-2. This study will greatly contribute to the existing knowledge of simulating wireless sensor networks with energy harvesting capabilities in ns-2. This paper will also serve as a basis for future research papers that make use of energy harvesting.

• 한국기계가공학회지
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• 제18권7호
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• pp.48-55
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• 2019

Soldiers have been exposed to the risk of chilblains in cold winters. Recent studies have described sensors and IOT devices that use independent power sources based on piezoelectric energy harvesting. Therefore, the heated shoes with an independent power source have been developed. For the application of energy harvesting to shoes, it is necessary to develop a unique harvester by considering human gait characteristics. Energy harvesters and ceramics were designed and fabricated in this study. The performances of these harvesters and ceramics were evaluated experimentally. Then, the harvesters and ceramics with superior performance were selected and applied to the system. Thereafter, the heating and charging performance of the system was tested under real walking conditions. The results show that the developed system can generate adequate energy to charge the battery and heat the shoes.

• 한국전기전자재료학회논문지
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• 제28권2호
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• pp.69-74
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• 2015

Recently, energy harvesting technology is increasing due to the fossil fuel shortages. Energy harvesting is generating electrical energy from wasted energies as sunlight, wind, waves, pressure, and vibration etc. Energy harvesting is one of the alternatives of fossil fuel. One of the energy harvesting technologies, the piezoelectric energy harvesting has been actively studied. Piezoelectric generating uses a positive piezoelectric effect which produces electrical energy when mechanical vibration is applied to the piezoelectric device. Piezoelectric energy harvesting has an advantage in that it is relatively not affected by weather, area and place. Also, stable and sustainable energy generation is possible. However, the output power is relatively low, so in this paper, newly designed honeycomb shaped piezoelectric energy harvesting device for increasing a generating efficiency. The output characteristics of the piezoelectric harvesting device were analyzed according to the change of parameters by using the finite element method analysis program. One model which has high output voltage was selected and a prototype of the honeycomb shaped piezoelectric harvesting device was fabricated. Experimental results from the fabricated device were compared to the analyzed results. After the AC-DC converting, the power of one honeycomb shaped piezoelectric energy harvesting device was measured 2.3[mW] at road resistance 5.1[$K{\Omega}$]. And output power was increased the number of harvesting device when piezoelectric energy harvesting device were connected in series and parallel.

• Journal of Biosystems Engineering
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• 제35권6호
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• pp.367-372
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• 2010

Consumption of pepper, a major spice vegetable used for seasoning Kimchi, continues to increase, but cultivation is in decline due to shortage of rural labor in Korea. The 39.2% of total labor requirement for conventional pepper cultivation was available for harvesting work. Therefore conventional manual harvesting should be turned to mechanical harvesting for labor-saving, cost-reducing and easy work. Surveys on conventional pepper cultivation patterns, labor requirements for various pepper cultivation works, and farmers' opinions on the mechanization of pepper harvesting were conducted to obtain basic informations. The labor requirement for pepper harvesting was 954 h/ha out of a total labor requirement of 2,436 h/ha for pepper cultivation. Harvesting was the hardest work, and hiring workmen for harvesting was also difficult. Farmers preferred to develop a small-scale pepper harvester using agricultural tractor or cultivar. Most farmer agreed to change cultivation pattern for mechanization of pepper harvesting, but hesitated to adopt new one-time-harvesting pepper varieties.

• 한국산학기술학회논문지
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• 제12권5호
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• pp.2048-2053
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• 2011

본 논문에서는 도어의 회전운동에 의해서 발생하는 기계에너지를 전기에너지로 변환시켜 에너지를 획득하는 시스템을 제안한다. 에너지를 획득하는 방법으로 2종류의 에너지 하베스터을 논의한다. 첫 번째, 도어의 회전축과 발전장치의 축을 기어장치로 직접 연결하여 발전하는 기어 축결합 에너지 하베스터, 두 번째로는 도어 선단을 발전장치의 스트링으로 연결하여 발전하는 스파이럴스프링 에너지 하베스터이다. 이 2종류의 하베스터를 제작하여 실험을 수행하며, 이 결과를 통해서 제안한 에너지 하베스터의 유효성을 나타낸다.

• Journal of Biosystems Engineering
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• 제31권6호
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• pp.500-505
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• 2006

Jujube is one of korean most favorite fruits. Harvesting operations of the jujube farming, however, completely depend on hand labor. Especially, collecting operation requires about three times of hand labor compared with separate operation by impacting or shaking of twigs in the hand-harvesting system of jujube fruits. Consequently, jujube farmers sincerely demand the mechanization of the collecting operation of jujube fruits in the harvesting operation. A new collecting system was designed and constructed five parts-collecting pad, guide ring system, sorting system, frame with driving system, and handle with operation levers, which performed collecting operation of jujube fruits without missing fruits in five part functions, however, an extra future more deliberate study would need how to handle conveniently the collecting pad of the prototype in the narrow space of row of the jujube farm.

• 항공우주시스템공학회지
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• 제10권3호
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• pp.15-22
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• 2016

The on-board appendages of satellites with mechanical moving parts such as the fly-wheel, the control-moment gyro, the cryocooler, and the gimbal-type directional antenna can generate an undesirable micro-vibration disturbance, which is one of the main causes of the image-quality degradation that affects high-resolution observation satellites. Consequently, the isolation of the micro-vibration issue has always been considered as salient, and the micro-vibration is therefore the focus of this study wherein a complex system that can provide the dual functions of a guaranteed vibration-isolation performance and electrical energy harvesting is proposed. The vibration-isolation and energy-harvesting performances of the complex system are predicted through a numerical analysis based on the characteristics that are obtained from component-level tests. In addition, the effectiveness of the complex system that is proposed in this study is verified through an assembly-level functional-performance test.