• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.423-428
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• 2009

Recently, the marine traffics have been increased along with enlargement of overseas commerce. Increasing the marine traffic may make higher the risk of marine accidents. Especially, the rate of accidents on costal area are more frequently. As if the marine safety information can be afforded to vessel and shore, the accident rate would be down. AIS AtoN is the navigational safety support device which is subject to functional requirements of IALA and technical standards of ITU. In this paper, we extend and implement the user-defined specification of AIS AtoN with message 21 for AIS basic information, messsage 6 for status report and message 12/14 for safety management.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.629-634
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• 2016

This paper describes the implementation of a ZigBee sensor node that can be utilized as a multiband and machine to machine (M2M) communication gateway. The IEEE 802.15.4-2003 standard was used as the wireless network frequency band. Ember's Type EM357 SoC was used as the transmission and reception device to perform the communication function, and it was also used for both the main M2M gateway and the sensor node. For the implementation of the operating protocol, EmberZNet Stack 4.5.4 from the Ember Corporation was used. The measurement of the reception sensitivity in the receiving module and the actual output signal from the reference were obtained from the transmission of a packet, and the packet included the M2M gateway within the attached ZigBee sensor. The packet error rate was measured as 0% with a -98 dBm reception sensitivity at the ZigBee frequency. In addition, excellent current characteristics of the ZigBee modules were shown by the implementation of the low-power circuit.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.7
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• pp.209-218
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• 2014

An AP that is used by smart device is going to be complicated because smart devices support diverse functions. As a result, multiple low-level IPs including a dedicated CPU are integrated in a high-level subsystem for supporting complicated function such as multimedia codec and camera. A subsystem has software that executes separately from main system, and the software needs to be initialized for every execution of the subsystem. This causes increase of the subsystem startup time so it should be improved because startup time of subsystem affects launching time of application. Methods in applied to computer system for fast startup also could be applied to fast startup of subsystem because subsystem is similar with computer system. In this paper, we apply snapshot method that is used in computer system to subsystem and analyzes the pros and cons. And snapshot method could not be applied to register of IP without modification because register of IP offers restricted read and write. So this paper suggests technique that applying snapshot to each characteristic of register.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.451-462
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• 2009

Recently, there are many active studies to enhance low I/O performance of hard disk device. The studies on the hardware make good progress whereas those of the system software to enhance I/O performance may not support the hardware performance due to its poor progress. In this paper, we propose a new method of prefetching n-blocks into the flash memory. The proposed method consists of three steps: (1)analyzing the pattern of read requests in block units; (2)determining the number of blocks prefetched to flash memory; (3)replacing blocks according to block replacement policy. The proposed method can reduce the latency time of hard disk and optimize the power consumption of the computer system. Experimental results show that the proposed dynamic n-block method provides better average response time than that of the existing AMP(Adaptive multi stream prefetching) method by 9.05% and reduces the average power consumption than that of the existing AMP method by 11.11%.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.6
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• pp.343-357
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• 2007

In this paper, we propose the techniques for effective management of profiles that necessary to provide adaptation content to an user. The profiles must be configured the related information of the user and can be exchanged according to periodic/aperiodic or event among user device, profile repository, contents adaptation server and contents storage server for providing adaptation content to an user. The profiles also must be supplied the contents services providers that need profiles for the adapted contents services. To support those function, we propose the management technologies of profiles and design profile framework supporting those. The proposed management framework of profiles is supported the profiles that are configurated using the various user's information and is used the Web Services for exchanging and providing regardless of the various devices and platform. The dynamic configuration method, metadata configuration method, and profiles providing methods using weight for effective management in the framework also are applied. The result of evaluation the proposed management techniques show effective profiles processing.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.1
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• pp.1-8
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• 2020

The thermal image device support image to detect infrared light from the object without light. It can use not only defence-related industry, but also civilian industry. This paper presents a new thermal image processing module using common image processor. The proposed module shows 10~20% performance improvement with normal mode and 50% performance improvement with sleep mode compared with the previously thermal image module based FPGA. and it guarantees high scalability according to modular system. In addition, the proposed module improves modulation and reuse, so it expect to have reduction of development period, low development cost. various application. In addition, it expect to have satisfaction of customer requirements, development design, development period, release date of product.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.172-178
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• 2015

The control moment gyroscope(CMG) which is well known as an effective high-torque-generating device is applicable to space vehicles, airplanes, ships, automobiles, robotics, etc. for attitude stabilization and maneuver. This paper deals with the overall details of 100Nm-class CMG development for various industrial applications, and provides the activities and results associated with the CMG system-level requirement analysis, the motor subsystem design/manufacturing/integration, the construction of ground support equipment, and the performance test and evaluation. The performance test reveals that the CMG generates the torque output more than 120Nm in as-designed operation of spin motor and gimbal motor.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.71-79
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• 2019

This study was conducted to examine the awareness and demands of parents and teachers on the use of IoT healthcare devices at daycare centers. A survey was conducted on 200 teachers and 200 parents. Collected data were analyzed by Frequency analysis, t-test, 𝑥2, using the SPSS WIN 22.0. The results of this study are as follows. First, teachers showed a higher level of preference for using IoT healthcare devices as they showed positive perception and support compared to parents, and showed higher recognition of information leakage than parents. Second, teachers and parents were most hoping to use IoT healthcare devices at emergency response in daycare-centers and had the highest demands for wearable devices. As a result of the both parents and teachers demand cost-sharing. Based on the results of this study, the possibility of utilizing IoT healthcare devices in daycare centers were discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.10
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• pp.1862-1878
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• 2011

With the advances in wireless communication technology and the advent of smartphones, research on location-based services (LBSs) is being actively carried out. In particular, several spatial index methods have been proposed to provide efficient LBSs. However, finding an optimal indexing method that balances query performance and index size remains a challenge in the case of wireless environments that have limited channel bandwidths and device resources (computational power, memory, and battery power). Thus, mechanisms that make existing spatial indexing techniques more efficient and highly applicable in resource-limited environments should be studied. Bitmap-based Spatial Indexing (BSI) has been designed to support LBSs, especially in wireless broadcast environments. However, the access latency in BSI is extremely large because of the large size of the bitmap, and this may lead to increases in the search time. In this paper, we introduce a Selective Bitmap-based Spatial Indexing (SBSI) technique. Then, we propose an Adaptive Bitmap-based Spatial Indexing (ABSI) to improve the tuning time in the proposed SBSI scheme. The ABSI is applied to the distribution of geographical objects in a grid by using the Hilbert curve (HC). With the information in the ABSI, grid cells that have no objects placed, (i.e., 0-bit information in the spatial bitmap index) are not tuned during a search. This leads to an improvement in the tuning time on the client side. We have carried out a performance evaluation and demonstrated that our SBSI and ABSI techniques outperform the existing bitmap-based DSI (B DSI) technique.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.127-138
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• 2009

Mobile web applications are being used and changed rapidly due to the growth of mobile device performance. But, cost of development environment and standards make the high development cost and low productivity. It is main reason that the design and implementation of the applications are more time consuming than general computing environments. In this paper, we propose MWeb(MobileWeb)-Framework based on the agile methodology and Ruby on Rails that is a kind of framework for supporting mobile web application development using mobile web standards. This work consists of the mobile web development architecture and agile process model. MWeb-Framework will support the same user experience to the different devices. We validates the framework by implementing the case studies through suggested mobile web development framework. As a result, we can develop the mobile web applications with productivity and quality. In the future, we will suggest how to make the MWeb-Framework standardization and practically apply the frameworks the various case studies to improve framework potentially problems.