• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.4
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• pp.314-319
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• 2019

In this study, we propose a W-band frequency modulated continuous wave(FMCW) radar altimeter that can measure the altitude based on the frequency differences of transmitted and received signals. This W-band FMCW system is powered by an altitude control algorithm, which we propose to help prevent collisions of drones with obstacles in real deployment by measuring the relative altitude. It is shown that this algorithm enables the drone to be positioned within a 3 % error of altitude from the desired input height. The chip used in the W-band transmitter and receiver was fabricated using a 65-nm CMOS process, and a horn antenna was directly fed by incorporating an embedded waveguide feeder into the chip. The clutter spectra observed in terrains including soil, grass, and calm lake water were measured and compared, confirming the reflectivity characteristics of various surfaces of different water contents.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.169-176
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• 2019

Wireless sensor networks are used to monitor and control areas in a variety of military and civilian areas such as battlefield surveillance, intrusion detection, disaster recovery, biological detection, and environmental monitoring. Since the sensor nodes are randomly placed in the area of interest, separation of the sensor network area may occur due to environmental obstacles or a sensor may not exist in some areas. Also, in the situation where the sensor node is placed in a non-relocatable place, some node may exhaust energy or physical hole of the sensor node may cause coverage hole. Coverage holes can affect the performance of the entire sensor network, such as reducing data reliability, changing network topologies, disconnecting data links, and degrading transmission load. It is possible to solve the problem that occurs in the coverage hole by finding a coverage hole in the sensor network and further arranging a new sensor node in the detected coverage hole. The existing coverage hole detection technique is based on the location of the sensor node, but it is inefficient to mount the GPS on the sensor node having limited resources, and performing other location information processing causes a lot of message transmission overhead. In this paper, we propose an Adjacent Matrix-based Hole Coverage Discovery(AMHCD) scheme based on connectivity of neighboring nodes. The method searches for whether the connectivity of the neighboring nodes constitutes a closed shape based on the adjacent matrix, and determines whether the node is an internal node or a boundary node. Therefore, the message overhead for the location information strokes does not occur and can be applied irrespective of the position information error.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.3
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• pp.133-141
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• 2020

In this paper, the communication method of data information accepted by underwater drones and the implementation method to console display of data information were described, and the function of integrated monitoring system interface and the design and implementation of sonar interface were explained. The operation and posture of underwater drones can be controlled using a controller connected to the console, and the distance information between underwater drones and obstacles is obtained from sonar so that they can be visually displayed on the console screen along with camera images. The integrated monitoring navigation console is implemented to suit improvements, making it convenient and easy for workers to use. In addition, by upgrading integrated monitoring and control software functions, the company added user-specific project management functions and the output of reports for hull inspection to make them different and competitive from other underwater drones.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.125-132
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• 2022

In this paper, we presented a cart which can automatically transport loads to the distribution center of the appointed indoor place, based on Raspberry pi 4. It can recognize the obstacles by using the ultrasonic sensors so that it prevents the collision and takes a detour. Further, we entered the direction control code in the RFID. It has installed at important points such as the intersections of the destinations, so that if the RFID reader of the cart senses the RFID, the cart would stop or change the direction. After the transportation, if the load cell(weight sensor) recognizes that the baggage is unloaded, the cart returns to the initial point and would be retrieved. Therefore, we embodied the transportation cart which reduces the use of manpower and solves the problems conveniently across the transportation strategies.

• Journal of Surface Science and Engineering
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• v.55 no.2
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• pp.51-62
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• 2022

Metal-organic framework (MOF) is one of the representative porous materials composed of metal ions and organic linkers. In spite of many advantages of the MOFs such as high specific surface area and ease of structure control, drawbacks have become obstacles to the practical use of them with poor electrical conductivity and chemical stability. The ZIF-8, which is consisted of zinc and imidazole linker, is one of the solutions to improve the chemical stability issue. In addition, composites using the ZIF-8 and carbonbased materials are widely used to enhance the electrical conductivity. In this regard, supercapacitor is very attractive field for using the composites, because most of carbon-based materials are porous and conductive. Also, for sensor applications, the ZIF-8 composite is suitable material to meet the requirement in terms of the selectivity and sensitivity. This review summarizes recent progress of the composite materials with the ZIF-8 and the carbon-based materials for the supercapacitors and the chemical sensors. In particular, the composites are classified into ZIF-8-graphene, ZIF-8-carbon nanotube and ZIF-8-other carbon-based material.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.211-219
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• 2022

Over the past decade, double-stranded RNA (dsRNA)-mediated gene silencing technology has progressed significantly for pest management in agriculture and for protecting beneficial insects from pathogens. Recently, breakthroughs in RNA interference (RNAi) applications for insect pest management by academia and commercial entities have provided RNAi products as commercial biopesticides. Although RNAi technology has vast potential and advantages for pest control, challenges, and limitations remain in practical applications. This review explores current challenges in the development of dsRNAs as a pest management tool and considers new approaches to overcome biological and environmental obstacles, such as poor stability and resistance.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.61-71
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• 2009

Vehicle license plate is the only way to check the registrated information of a vehicle. Many works have been devoted to the vision system of recognizing the license plate, which has been widely used to control an illegal parking. However, it is difficult to correctly segment characters on the license plate since an illumination is affected by a weather change and a neighboring obstacles. This paper proposes a robust method of segmenting the character of the license plate on irregular illumination condition. The proposed method enhance the contrast of license plate images using the Chi-Square probability density function. For segmenting characters on the license plate, binary images with the high quality are gained by applying the adaptive threshold. Preprocessing and labeling algorithm are used to eliminate noises existing during the whole segmentation process. Finally, profiling method is applied to segment characters on license plate from binary images.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.21-43
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• 2015

Korean floricultural industry has grown under the full backing of government, as it placed itself as the main export item since 2000s. Despite its high-speed growth after the domestic production scale of trillion won, the floricultural industry lost its pace after 2005, due to the market-opening of agricultural product and global economic depression. Although the national income is growing and the level of civilized living is following, spending on flowers is faltering. As of such circumstances, necessity for analyzing flower consumption trend and behavior has came out, along with the calls for expansion plan of flower consumption, under the basis of result analysis on consumer reports. The result of the research contains the trend/consumption behavior analysis on domestic and foreign flower industry to boost floricultural industry, along with reviews on various studies of the developmental process of domestic and foreign cut-flowers/pot-plants consumption trend. Also this study has reached to the various recognition of people toward flower, through a public survey. Through such results, this study would like to propose the measures for diffusion of flower-consumption culture, achieving the improvement of life-quality of public along. First, efforts on reviewing the customer accessibility is essential to create flower- culture and the consumption. Second, to eliminate the obstacles that prevents flowers from public's daily life is essential. Third is the effective public-relations on flowers. To create consuming culture and to adhere the positive images, it is essential to research and systematically organize categories of color, scent, and elements of flower and utilize them. Last proposal is the organization of flower-concerned personnels and the leading groups. The change is affected by the economical, social environment, along with the emotions of consumers. Therefore the necessity for the leading group to be the control-tower of such changes are very clear.

• SUVANNABHUMI
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• v.6 no.2
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• pp.3-18
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• 2014

With natural resources-terrestrial or coastal-fastly diminishing, governments are now resorting to biodiversity conservation, fast-tracking the introduction of new legislations, as well as the amendment of existing ones, and laying out programs that interpret existing practices and research agendas. This paper examines how biodiversity conservation-in addition to eco-tourism-has become an important symbol of the modernizing state of Sabah, Malaysia. It further examines the effects of biodiversity conservation on state and community management of natural resources, with particular reference to the management of natural resources by the indigenous peoples of Sabah. Citing case studies and focusing on a forest community at Kiau Nuluh, in the district of Kota Belud, Sabah, this paper evaluates strategies used by indigenous groups to maintain access and control over the management of natural resources-and by implication to livelihoods-via ecotourism, making creative alliances with non-government organisations as well as forging cooperation with government agencies which act as custodians of these resources. For a majority of indigenous groups however, the practice of biodiversity conservation has meant reduced and controlled access to natural resources, considering the fundamental issue of the lack of security of tenure to the land claimed under customary rights. New initiatives at recognizing Indigenous and Community Conserved Areas (ICCAs) by international conservation groups provide a means for tenure recognition, for a price, of course. The recognition of ICCAs also faces obstacles arising from developmentalist ideology which upholds that forests are valuable only when converted to other land use, and not left to stand for their intrinsic value.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.747-754
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• 2023

Energy-efficient routing protocol is an important task in a wireless sensor network that is used for monitoring and control by wirelessly collecting information obtained from sensor nodes deployed in various environments. Various routing techniques have been studied for this, but it is also necessary to consider WSN environments with specific situations and conditions. In particular, due to topographical characteristics or specific obstacles, a hole where sensor nodes are not deployed may exist in most WSN environments, which may result in inefficient routing or routing failures. In this case, the geographical routing-based hall bypass routing method using GPS functions will form the most efficient path, but sensors with GPS functions have the disadvantage of being expensive and consuming energy. Therefore, we would like to find the boundary node of the hole in a WSN environment with holes through minimal sensor function and propose hole bypass routing through boundary line formation.