• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.674-680
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• 2008

An SDR (Software Defined Radio) system based on general purpose computing platform has benefits of ease of software development process, high degree of software compatibility, and cost-effectiveness of general purpose processors. This paper discusses design and implementation of a dual-mode SDR system that supports both cordless phone and walkie-talky system running on Linux-based general purpose computing platform. For this purpose, we designed modulation and demodulation software on open source-based GNU radio middleware. We also designed a customized RF front-end hardware which performs frequency conversion between RF and IF. The proposed SDR system successfully exhibited its ability to operate both cordless phone and walkie-talky communication on Intel processor-based general purpose computing platform. But experience with the prototype SDR system shows that further research is required for run-time software reconfiguration and efficient integration with conventional TCP/IP protocol stacks.

• Proceedings of the Korea Port Economic Association Conference
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• 2006.08a
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• pp.277-290
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• 2006

A shipping operation broadly breaks down into: the acquisition of the ship, securing income from the ships, operating the ships, and running the business. For all ships these functions have to be performed. But most important thing is whether it is a better option for some or all these activities to be undertaken by a third party manager rather than resource them in-house or not. However, the size of ship management market has been increasing continuously over the last decades to achieve cost-savings. The ship management is considered as creating high added value and contributing to national economic growth. This paper will analyzes development trends of ship management and market, and carry out comparative studies with Korean ship management companies and an empirical studies on selection criteria of ship management firms. In doing so, some implications and alternatives will be suggested in order for Korean ship management companies to create high added value and gain international competitive edge.

• Wind and Structures
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• v.27 no.6
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• pp.399-416
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• 2018

In order to reveal the independent relationship between track irregularity and wind loads, the stochastic characteristics of train-bridge coupling systems subjected to wind loads were investigated by the multi-sample calculation. The vehicle was selected as 23 degrees of freedom dynamical model, and the bridge was described by three-dimensional finite element model. It was assumed that the wind loads were random processes with strong spatial correlation, while the track irregularities were stationary random ones. As a case study, a high-speed train running on a cable-stayed bridge subjected to wind loads was studied. The effect of rail irregularities was deemed to be independent of the effect of wind excitations on the coupling system in the same wind circumstance for the same project, leading to the conclusion that the effect of wind loads and moving vehicle could be calculated separately. The variance results of the stochastic responses of vehicle-bridge coupling system under the action of wind loads and rail irregularities together were equivalent to the sum of the variance of the responses induced by each excitation. Therefore, when one of the input excitations is different, only the effect of changed loads needs to be assessed. Moreover, the new calculated results were combined with the effect of unchanged loads to present the stochastic response of coupling system subjected to the different excitations, reducing the cost of computations. The stochastic characteristics, the CFD (cumulative distribution function) of the coupling system with different wind velocities, vehicle speed, and vehicle marshalling were studied likewise.

• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.393-399
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• 2018

The development of unmanned AI continues, and the development of AI unmanned is aimed at more efficiently, accurately, and speedily the work that has been resolved by manpower such as industry, welfare, and manpower. AI unmanned technology is evolving in various places, and it is time to switch to unmanned systems from many industries and factories. We take this into consideration, and use the Deep Learning technology, which is one of the core technologies of artificial intelligence (AI), not the manpower but the fruits that pour the rails at once in a large orchard. We want to study the unmanned fruit sorting machine that can be operated under manager's supervision without dividing the fruit by type and grade and dividing by country of origin and grade. This unmanned automated classification system aims to reduce the labor cost by minimizing the manpower and to improve the

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.147-151
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• 2014

With the advent of tiny and inexpensive computer systems like Raspberry Pi, it has become possible to construct an experimental environment of MANETs (Mobile Ad hoc Networks) at a relatively low cost. In this paper, we implement a node of MANETs with a Raspberry Pi equipped with two 802.11 wireless LAN cards and dynamic routing software running on it. In an outdoor MANETs environment with moving mobile nodes automatically rebuilding broken routes, we conducted a real-time video streaming experiment over the MANET. The video stream is transmitted from a node with a video camera installed on it to another node through the route established dynamically. Each node is equipped with a display device, with which the current status of the node can be checked out. We also implemented software that automatically collects data stored in each node and analyzes the performance of the MANETs. Through this experiment, we could evaluate the performance of realistic video streaming service in a MANETs environment.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.129-138
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• 2021

Today we are getting a lot of information and various activities on our website through the internet. These websites are maintained by individuals or by website specialists. The basic method is to change the files that make up the running website. Changing the entire file in this process takes a long time and changes the files that do not need to be changed, so the efficiency is greatly reduced. When only the files that need to be changed are changed, it takes a lot of effort as a person must manually search each path to check the files and change the files one by one. To solve this problem, automatic distribution systems were developed. Additional resources and learning are required, resulting in additional cost, time and labor. Therefore, in this paper, we propose an automatic update system to minimize resource consumption by using the resources and technologies of the existing website. The proposed system does not require learning new skills. This aims to improve reliability and reduce time compared to human work.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.871-874
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• 2011

The fast emerging of network technology and the high demand of computing resources have prompted many organizations to outsource their storage and computing needs. Cloud based storage services such as Microsoft's Azure and Amazon's S3 allow customers to store and retrieve any amount of data, at anytime from anywhere via internet. The scalable and dynamic of the cloud storage services help their customer to reduce IT administration and maintenance costs. No doubt, cloud based storage services brought a lot of benefits to its customer by significantly reducing cost through optimization increased operating and economic efficiencies. However without appropriate security and privacy solution in place, it could become major issues to the organization. As data get produced, transferred and stored at off premise and multi tenant cloud based storage, it becomes vulnerable to unauthorized disclosure and unauthorized modification. An attacker able to change or modify data while data inflight or when data is stored on disk, so it is very important to secure data during its entire life-cycle. The traditional cryptography primitives for the purpose of data security protection cannot be directly adopted due to user's lose control of data under off premises cloud server. Secondly cloud based storage is not just a third party data warehouse, the data stored in cloud are frequently update by the users and lastly cloud computing is running in a simultaneous, cooperated and distributed manner. In our proposed mechanism we protect the integrity, authentication and confidentiality of cloud based data with the encrypt- then-upload concept. We modified and applied proxy re-encryption protocol in our proposed scheme. The whole process does not reveal the clear data to any third party including the cloud provider at any stage, this helps to make sure only the authorized user who own corresponding token able to access the data as well as preventing data from being shared without any permission from data owner. Besides, preventing the cloud storage providers from unauthorized access and making illegal authorization to access the data, our scheme also protect the data integrity by using hash function.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.129-134
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• 2017

In the present society, our current technology associated with bakery industry has been improved as much as technical development can get abreast of the Western one where the bread has originated and has been awarded and ranked in the highest level of many bakery or pastry competitions. In these trends, many people are running for high value added business such as bakery industry and bakery $caf{\acute{e}}$, etc. with big interest. However, high labor cost of technician and difficulties in human resource management become obstruction factors in the growth of the bakery industries. Therefore, in this paper, the designed system for both dividing and rounding dough quickly and exactly at the same time was studied. The main function of this system is to divide the original dough into 3 tracks and then, to place 4 doughs in the inner track, 12 doughs in the mid track, 20 doughs in the outer track, totally 36 doughs in a routine. It takes much energy because 36 doughs can be completed in a routine. Therefore, this system uses hydraulic pressure and a 0.75Kw induction motor is used for dough rounding. This system can make primarily fermented dough into 36 divided doughs very quickly and exactly on a guide panel at the desired weight by dividing it within 1-9 seconds and by rounding each within 1-9 seconds. This system is very effective in bakery industry to minimize labor cost and it is expected to supply more hygienic products to the customers.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.135-146
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• 2004

For improving the effectiveness of travel information, some rational paths are needed to provide them to users driving in real road network. To meet it, k-shortest path algorithms have been used in general. Although the k-shortest path algorithm can provide several alternative paths, it has inherent limit of heavy overlapping among derived paths, which nay lead to incorrect travel information to the users. In case of considering the network consisting of several turn prohibitions popularly adopted in real world network, it makes difficult for the traditional network optimization technique to deal with. Banned and penalized turns are not described appropriately for in the standard node/link method of network definition with intersections represented by nodes only. Such problem could be solved by expansion technique adding extra links and nodes to the network for describing turn penalties, but this method could not apply to large networks as well as dynamic case due to its overwhelming additional works. This paper proposes a link-based shortest path algorithm for the travel information in real road network where exists turn prohibitions. It enables to provide efficient alternative paths under consideration of overlaps among paths. The algorithm builds each path based on the degree of overlapping between each path and stops building new path when the degree of overlapping ratio exceeds its criterion. Because proposed algorithm builds the shortest path based on the link-end cost instead or node cost and constructs path between origin and destination by link connection, the network expansion does not require. Thus it is possible to save the time or network modification and of computer running. Some numerical examples are used for test of the model proposed in the paper.

• Journal of Animal Environmental Science
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• v.14 no.1
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• pp.23-30
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• 2008

The objective of this study was to estimate the optimum scale of PLMTP (Public Livestock Manure Treatment Plant) for the efficient management of public sector by long-run cost function. An economic analysis was performed using the survey of 52 PLMTP records collected by Ministry of Environment in 2007. The main results obtained in this study can be summed up as follows. The optimum scale under given environmental conditions turned out to be $180{\sim}200m^3$/day which is almost $1.5{\sim}1.6$ times of the average scale of sample plants, $146m^3$/day. This gap between the optimum and current scale suggests that there remains the possibility of further expansion of scale.