• Title/Summary/Keyword: optimal harvesting

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Analysis of the Timber Harvesting Potential of the Garisan Leading Forest Management Complex in Hongcheon (홍천 가리산 선도산림경영단지의 목재생산 잠재량 분석)

  • Young-Hwan Kim;Dong-ho Lee;Min-jae Cho;Jin-Woo Park
    • Journal of Korean Society of Forest Science
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    • v.112 no.4
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    • pp.523-529
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    • 2023
  • The aim of this study was to analyze the potential for timber harvesting in the Hongchoen Garisan Leading Forest Management Complex in the national forests, and to suggest an optimal target yield for sustainable timber harvesting. The potential for timber harvesting was assessed by analyzing the area available for timber harvesting using GIS spatial analysis, but excluding areas with a slope of more than 40° (topographical constraints), areas within 30 m on both sides of streams (environmental constraints), and areas more than 300 m away from forest roads (technical constraints). The analysis identified 3,298 ha (49%) of the total complex area of 6,679 ha as available for timber harvesting, yielding a potential harvesting volume of 608,613 m3. In the case of coniferous plantations, the potential harvesting volume was 409,721 m3, which was a very high level that accounted for 67.3% of the total. We also conducted an optimization analysis to minimize the differences in area between age classes, while maintaining sustainable timber harvesting for the next 50 years. An annual average of 41.9 ha (7,988 m3) was determined to be the optimal timber yield, and in this case, it was possible to convert the age class structure to a more stable structure after 50 years.

Detecting on Optimal Seeding and Harvesting Dates of Whole Crop Maize via Meta Data (사일리지용 옥수수의 메타자료를 이용한 적정 파종 및 수확시기의 탐색)

  • Jo, Hyun Wook;Kim, Si Chul;Kim, Moon Ju;Kim, Ji Yung;Jo, Mu Hwan;Kim, Byong Wan;Sung, Kyung Il
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.40 no.1
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    • pp.66-72
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    • 2020
  • This study aimed to discuss the optimal seeding and harvesting dates with growing degree days(GDD) via meta-data of whole crop maize(WCM). The raw data (n=3,152) contains cultivation year, cultivars, location, seeding and harvesting dates collected from various reports such as thesis, science journals and research reports (1982-2012). The processing was: recording, screening and modification of errors; Then, the final dataset (n=121) consists of seeding cases (n=29), and harvesting cases (n=92) which were used to detect the optimum. In addition, the optimal periods considering tolerance range and GDD also were estimated. As a result, the optimum seeding and harvesting periods were 14th April ~ 3rd May and 15th August ~ 4th September, respectively; where, their GDDs were 23.7~99.6℃ and 1,328.7~1,602.1℃, respectively. These GDDs could be used as a judge standard for selecting the seeding and harvesting dates.

Design and analysis of vibration micro piezoelectric energy harvesting for wireless sensor nodes (무선 센서 노드용 진동형 마이크로 압전 에너지 하베스팅 설계 및 분석)

  • Yoon, Kyu-Hyung;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.277-277
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    • 2009
  • In this paper, PMPG (Piezoelectric Micro Power Generator) was investigated by ANSYS FEA (Finite Element Analysis) to decrease operating frequency and improve out power. The micro power generator was designed to convert ambient vibration energy to electrical power as a ZnO piezoelectric material. To find optimal model in low vibration ambient, the shape of power generator was changed with different membrane width, thickness, length, and proof mass size. Used the ANSYS modal analysis, bending mode and stress distribution of optimal model were analyzed. Also, the displacement with the frequency range was analyzed by harmonic analysis. From the simulation results, the resonance frequency of optimal model is about 373 Hz and confirmed the possibility of ZnO micro power generator for wireless sensor node applications.

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Opportunistic Spectrum Access Using Optimal Control Policy in RF Energy Harvesting Cognitive Radio Networks (무선 에너지 하비스팅 인지 무선 네트워크에서 최적화 제어 정책을 이용한 선택적 스펙트럼 접근)

  • Jung, Jun Hee;Hwang, Yu Min;Cha, Gyeong Hyeon;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.10 no.3
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    • pp.6-10
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    • 2015
  • RF energy harvesting technology is a promising technology for generating the electrical power from ambient RF signal to operate low-power consumption devices(eg. sensor) in wireless communication networks. This paper, motivated by this and building upon existing CR(Cognitive Radio) network model, proposes a optimal control policy for RF energy harvesting CR networks model where secondary users that have low power consumption harvest ambient RF energy from transmission by nearby active primary users, while periodically sensing and opportunistically accessing the licensed spectrum to the primary user's network. We consider that primary users and secondary users are distributed as Poisson point processes and contact with their intended receivers at fixed distances. Finally we can derive the optimal frame duration, transmission power and density of secondary user from the proposed model that can maximize the secondary users's throughput under the given several conditions and suggest future directions of research.

Electric energy harvesting using piezoelectric actuator driven by geared motor (압전 액추에이터를 이용한 에너지 수확)

  • Yun, So-Nam;Kim, Dong-Gun;Ham, Young-Bog;Park, Jung-Ho;Choi, Sang-Kyu
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1463-1468
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    • 2007
  • This paper presents the possibility of the electric energy harvesting using piezoelectric actuator which is operated by geared motor. The geared motor consisting of oval shape cam and speed controller was operated in the range of 40${\sim}$172rpm. The PZT actuator of $36L{\times}13W{\times}0.6H$ was used for energy harvesting and the results of the theoretical model were verified by comparing it with the measured response of a experimental setup. Experimental study for obtaining the optimal operating conditions, such as displacement variation of the PZT actuator and motor speed variation, was achieved. A power of 0.02mW at the geared motor speed of 172rpm and the PZT actuator maximum displacement of $500{\mu}m$ was measured. In this study, it was confirmed that the wind power can be used for MEMS based sensor operating and windmill health monitoring one.

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Development of Piezoelectric Energy Harvesting Device activated by Wind (바람에 의해 구동되는 압전에너지 수집 장치 개발)

  • Lee, Haeng-Woo;Kwak, Moon-K.;Yang, Dong-Ho;Lee, Han-Dong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.76-77
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    • 2009
  • This paper is concerned with the development of the piezoelectric energy harvesting(PEH) device using Wind. In this study, the piezoelectric energy harvesting system consisting of a cantilever with a pinwheel and piezoelectric wafer was investigated in detail both theoretically and experimentally. The power output characteristics of the PEH was then calculated and discussed. Theoretical and experimental results showed that the PEH was able to charge a battery with ambient vibrations but still needed an effective mechanism which can convert mechanical energy to electrical energy and an optimal electric circuit which dissipates small energy.

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Optimization of Microalgae Harvesting Using Flocculation and Dissolved Air Floatation (Flocculation과 Dissolved Air Floatation을 이용한 미세조류 수확 최적화)

  • Kwon, Hyuck-Jin;Jung, Chang-Kyou;Kim, Nam-Hoon;Lee, Jin-Won
    • KSBB Journal
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    • v.27 no.2
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    • pp.103-108
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    • 2012
  • The harvesting of microalgae is a critical step that precedes biodiesel conversion. The most widely used harvesting technology is flocculation and floatation. In this study, the efficiency of the flocculants aluminum sulfate and poly aluminum chloride were evaluated for harvesting the alga Dunaliella tertiolecta in conjunction with dissolved air floatation. Using the jar test the optimum concentration range for aluminum sulfate was 1.0~1.5 g/L and for poly aluminium chloride, 1.5~2.0 g/L. The degree of coagulation was visualized by microscopy. Further analysis in combination with dissolved air floatation showed that the optimal concentration for aluminum sulfate was 1.1 g/L and for poly aluminum chloride, 1.6 g/L.

Energy Efficient Resource Allocation with Energy Harvesting in Cognitive Radio Networks (인지 라디오 네트워크에서 에너지 하베스팅을 고려한 에너지 효율적 자원 할당 방안)

  • Lee, Kisong;Lee, Woongsup
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.7
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    • pp.1255-1261
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    • 2016
  • Recently, the energy harvesting technology in which energy is collected from the wireless signal which is transmitted by mobile communication devices, has been considered as a novel way to improve the life time of wireless sensors by mitigating the lack of power supply problem. In this paper, we consider the optimal sensing time and power allocation problem for cognitive radio systems, where the energy efficiency of secondary user is maximized while the constraint are satisfied, using the optimization technique. Based on the derived optimal solutions, we also have proposed an iterative resource allocation algorithm in which the optimal power and sensing time allocation can be found without excessive computations. The simulation results confirm that the proposed scheme achieves the optimal performance and it outperforms the conventional resource allocation schemes in terms of energy efficiency while the constraints are guaranteed to be satisfied.

Energy Harvesting in Multi-relay Multiuser Networks based on Two-step Selection Scheme

  • Guo, Weidong;Tian, Houyuan;Wang, Qing
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.9
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    • pp.4180-4196
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    • 2017
  • In this paper, we analyze average capacity of an amplify-and-forward (AF) cooperative communication system model in multi-relay multiuser networks. In contrast to conventional cooperative networks, relays in the considered network have no embedded energy supply. They need to rely on the energy harvested from the signals broadcasted by the source for their cooperative information transmission. Based on this structure, a two-step selection scheme is proposed considering both channel state information (CSI) and battery status of relays. Assuming each relay has infinite or finite energy storage for accumulating the energy, we use the infinite or finite Markov chain to capture the evolution of relay batteries and certain simplified assumptions to reduce computational complexity of the Markov chain analysis. The approximate closed-form expressions for the average capacity of the proposed scheme are derived. All theoretical results are validated by numerical simulations. The impacts of the system parameters, such as relay or user number, energy harvesting threshold and battery size, on the capacity performance are extensively investigated. Results show that although the performance of our scheme is inferior to the optimal joint selection scheme, it is still a practical scheme because its complexity is much lower than that of the optimal scheme.

A scheme for efficient data transmission and energy harvesting in drone systems using time-power switching (Time-Power 제어를 이용한 드론의 효율적 데이터 전송 및 에너지 하비스팅 기법)

  • Hong, Seung Gwan;Cha, Gyeong Hyeon;Lee, Sun Yui;Hwang, Yu Min;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.10 no.4
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    • pp.71-76
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    • 2015
  • In this paper, we propose a system model which effectively transmits the data and conducts RF energy harvesting in a wireless communication network of LTE and 5G. Through time switching and power splitting schemes, we find a time & power ratio to show the good performance according to the standard that we set up for transmitting a signal and conducting RF energy harvesting. So selecting optimal time & power ratio, we can efficiently transfer data to other drones and harvest the amount of harvested power simultaneously we desire. Also, according to conducting the performance analysis, we can compare an ideal receiver with the proposed system model. And, we suggest a future direction of research.