• Convergence Security Journal
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• v.7 no.3
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• pp.87-93
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• 2007

We propose a mobile point-of-sale system, which consists of only mobile information terminals and personal computers. The proposed system provides most of functionalities related with resource planning, adminstration and management, provided by medium-scale or large-scale POS systems, with additional functionalities, such as automatic information gathering and management through mobile interconnection, while eliminating the necessity of additional special-purpose devices, such as bar-code systems. The proposed system transmits order information through wireless and wired communication lines, thus allowing real-time sharing of order information among diverse information devices, such as mobile order receiving terminals, main server within stores, monitors and printers located in production lines. Also, the system is able to transfer such detail information produced within stores in real-time to the enterprise-level accounting, sales, logistics, personnel management system, which facilitate enterprise-wide management and administrative decision-making. No additional programs are required for mobile terminals. Order information received by such terminals are entered into databases through web server of main server and that information is again transferred to main server and production line printers. The proposed system can handle all the point-of-sale information and can provide almost of the POS functionalities by simply utilizing wireless internet, personal computers, and mobile terminals without installing specific-purpose peripheral devices. The proposed system can be widely applied to the small-scale stores and will contribute in reducing construction and maintenance cost required for point-of-sale management.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.744-753
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• 2015

This paper presents the results of research on developing marine unified communications to provide VoIP service based on marine satellites. With the recent popularity of smart-phones and other mobile devices, the demand for Internet-based wired and wireless unified technology has been growing in marine environments, and increasing interest is being directed to VoIP products and service models with high price competitiveness and the ability to deliver a variety of services. In this regard, this research designed three instruments, developed their unit modules, and verified their performances. These three instruments included the following: (1) a marine VoIP module equipped with an analogue gateway that can be linked to the existing devices used in vessels, which is more than 80% smaller than that of a land system; (2) a text/voice/video engine for marine satellite communications that runs on technology that minimizes communication data usage, which is a core technology for a marine VoIP service; and (3) a unified communication service that can support multilateral cloud-based message conversations, telephone number-based call functions, and voice/video calling between a private space in a ship and shore.

• The KIPS Transactions:PartC
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• v.17C no.6
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• pp.441-450
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• 2010

Recently, a lot of interest is increased in sensor network which gathers various data through many sensor nodes deployed in wired and wireless network environment. However, because of the limitation in memory, computation, and energy of the sensor nodes, security problem is very important issue. In sensor network, not only the security problem, but also computing power should be seriously considered. In this paper, considering these characteristics, we make the sensor network consist of normal sensor nodes and clusterheaders with enough space and computing power, and propose a group key rekeying scheme adopting PCGR(Predistribution and local Collaborationbased Group Rekeying) for secure group communication. In our proposal, we enhance the security by minimizing the risk to safety of the entire network through verifying the new key value from clusterheader by sensor nodes. That is, to update the group keys, clusterheaders confirm sensor nodes through verifying the information from sensor nodes and send the new group keys back to authentic member nodes. The group keys sent back by the clusterheaders are verified again by sensor nodes. Through this mutual authentication, we can check if clusterheaders are compromised or not. Qualnet simulation result shows that our scheme not only guarantees secure group key rekeying but also decreasesstorage and communication overhead.

• Journal of Information Technology Services
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• v.1 no.1
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• pp.57-66
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• 2002

We are looking at the two different kinds of IT on this paper. One is VoIP and the other is VR (voice recognition). We are more interesting at the evolving techniques and services produced by combining the two techniques mentioned above. Recently, there are so many services and products appeared in the market using voice recognition technique. Now the technique has progressed on the level that can even replace the user interfaces using the QUI or general DTMF. Therefore, we are expecting so many various new services showed UP In the market which is combination of the VoIP and VR. Up until now, three models are available in the field which are wired telephone, wireless telephone, and wireless internet. We know the effectiveness of the VoIP is maximized more when this technique is combined with others rather than used alone without other techniques.

• Progress in Medical Physics
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• v.14 no.2
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• pp.124-130
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• 2003

Currently, as a consequence of PACS (Picture Archiving Communication System) implementation many hospitals are replacing conventional film-type interpretations of diagnostic medical images with new digital-format interpretations that can also be saved, and retrieve However, the big limitation in PACS is considered to be the lack of mobility. The purpose of this study is to determine the optimal communication packet size. This was done by considering the terms occurred in the wireless communication. After encoding medical image using JPGE2000 image compression method, This method embodied auto-error correction technique preventing the loss of packets occurred during wireless communication. A PC class server, with capabilities to load, collect data, save images, and connect with other network, was installed. Image data were compressed using JPEG2000 algorithm which supports the capability of high energy density and compression ratio, to communicate through a wireless network. Image data were also transmitted in block units coeded by JPEG2000 to prevent the loss of the packets in a wireless network. When JPGE2000 image data were decoded in a PUA (Personal Digital Assistant), it was instantaneous for a MR (Magnetic Resonance) head image of 256${\times}$256 pixels, while it took approximately 5 seconds to decode a CR (Computed Radiography) chest image of 800${\times}$790 pixels. In the transmission of the image data using a CDMA 1X module (Code-Division Multiple Access 1st Generation), 256 byte/sec was considered a stable transmission rate, but packets were lost in the intervals at the transmission rate of 1Kbyte/sec. However, even with a transmission rate above 1 Kbyte/sec, packets were not lost in wireless LAN. Current PACS are not compatible with wireless networks. because it does not have an interface between wired and wireless. Thus, the mobile JPEG2000 image viewing system was developed in order to complement mobility-a limitation in PACS. Moreover, the weak-connections of the wireless network was enhanced by re-transmitting image data within a limitations The results of this study are expected to play an interface role between the current wired-networks PACS and the mobile devices.