• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.106-116
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• 2018

Recently, the role of the contact center for business-to-consumer (B2C) operations is becoming more and more important as the customer contact point. In particular, an Internet Protocol (IP)-based contact center system is made up of a complicated information system in order to accommodate various customer channels, in addition to the telephone, and to respond in real time. However, until now, evaluations of contact centers have focused on customer service-based research from inbound contact centers. We used the contact center as a measure of performance, focusing on indicators that have traditionally influenced customer satisfaction, such as response rates and service levels. There is insufficient research on the characteristics of the services that a contact center should have and on the evaluation models for information systems. The role of information systems is becoming important as the latest contact center, which has moved from the TDM-driven digital phone system center to the IP-based contact center, accommodates a variety of digital channels other than voice phones. In particular, as offline branches decrease due to the development of the Internet and mobile phones, non-facing responses to customers are important, so the contact center has influenced the enterprise. Therefore, we developed an evaluation model not only in terms of customer service, but also from information system and business aspects, using the AHP and verifying the evaluation model through empirical cases. In particular, content analysis was used to ensure objectivity of AHP evaluation items.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.219-224
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• 2011

To improve medical service and customers' satisfaction by reducing actual waiting time for medical inspection by personalized examination guidance contents (PEGC) linked with medical information system (MIS). The suggested PEGC was completed with preparing transmission for data and PEGC by using transmission control protocol internet protocol (TCP/IP) which can be built up creditable data transmission service. When patient signal event appeared in MIS while the communication was in standby, the ID and data of the customer were shown as text and image on monitors in waiting room. Guiding inspections, steps of examination, and undressing information extracted from the PEGC was also shown to the appropriate patient. After installation of the suggested PEGC, we rechecked satisfaction rates of 60 customers who visited the hospital with a same method as initial survey. The results of this study suggest that 3.6 point of waiting time satisfaction index were improved, after installation of the suggested PEGC, as 4.6 point.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.778-782
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• 2008

The performance in combination of wired and wireless mesh network which will be a main access network in future internet is directly linked with service quality to users. In this paper, we evaluate variant TCP performance and analyze traffic characteristics on Wireless (Seoul National University Mesh testbed) - Wired (KOREN/Abilene) - Wireless (HP Mesh testbed in the USA) Network. We found that RTT is proper in this network to serve a VoIP service. Also we propose an enhanced TCP protocol which can perform well in both wireless network which has many packet losses and wired network which has high bandwidth and long delay.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1602-1608
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• 2013

PoC (Push-to-Talk over Cellular) provides one-to-one as well as one-to-many communications with VoIP technology based on SIP over cellular networks. According to above property, PoC is considered as perscrptive technology for public protection for disaster relief networks. For this networks, group communication is the essential function. However, since current standardization process takes into general scenarios account without any consideration for mentioned networks, it have some problems in the point of adaptability. To solve above problem, in this paper, we propose how to reduce the overhead on the PoC server to reduce the transmission delay. Simulation results are shown to evaluate the improved performance.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.3
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• pp.246-256
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• 2020

In the future Network Centric Warfare(NCW), changing to IPv6 based network environment is required to enable various future technologies such as the Internet of Things(IoT) and cloud technology which are expected to be introduced to the tactical network evolution. With the change to the IPv6 network, an ID/LOC(Identifier/Location) separation protocol that decomposes context of the IP address to location and identifier can enhance network capacity of increasing number of device and provide efficient mobility management in the tactical network that changes topology dynamically. In this paper, we choose ILNP(Identifier-Locator Network Protocol) as an ID/LOC separation for tactical network environment. In addition to ILNP-based tactical network design, this paper proposes a network-based mobility management scheme for providing efficient mobility management. Through numerical performance analysis, we show that the proposed scheme can reduce network loads more effectively than the conventional IP-based mobility management scheme and common handover procedure in ILNP.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.21-26
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• 2009

Presently, the demand for IPTV, to satisfy a variety of goals, is exploding. IPTV is coming into the spotlight as a killer application in upcoming IP convergence networks such as triple play which is the delivery of voice, internet, and video service to a subscriber. IPTV utilizes CAS, which controls the subscriber access to content for a profit. Although the current CAS scheme provides access control via subscriber authentication, there is no authentication scheme for the content transmitted from service providers. Thus, there is a vulnerability of security, through which an adversary can forge content between the service provider and subscribers and distribute malicious content to subscribers. In this paper, based on a hash tree scheme, we proposed efficient and strong source authentication protocols which remove the vulnerability of the current IPTV system. We also evaluate our protocol from a view of IPTV requirements.

• Convergence Security Journal
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• v.20 no.5
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• pp.3-10
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• 2020

Recently, the Internet and networks are regarded as essential infrastructures that constitute society, and security threats have been constantly increased. However, the network switch that actually transmits packets in the network can cope with security threats only through firewall or network access control based on fixed rules, so the effective defense for the security threats is extremely limited in the network itself and not actively responding as well. In this paper, we propose an in-network security framework using the high-level data plane programming language, P4 (Programming Protocol-independent Packet Processor), to deal with DDoS attacks and IP spoofing attacks at the network level by monitoring all flows in the network in real time and processing specific security attack packets at the P4 switch. In addition, by allowing the P4 switch to apply the network user's or administrator's policy through the SDN (Software-Defined Network) controller, various security requirements in the network application environment can be reflected.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8357-8362
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• 2015

The emergency call device has been installed and operated for the elevator passenger safety, but the call can not be connected or delay to the operator in an emergency. The application of the Internet of Things(IoT) technology is required for the systematic management and reliability of the emergency call device installed in the elevator. To meet these requirements it is necessary to apply the RMS(Remote Management System). Emergency call device periodically reports the operating status information and the emergency call history information of the emergency call device to the RMS in the PSTN(Public Switched Telephone Network) environment, and transmits the call request information in an emergency. RAS(Remote Access Server) plays a role of converting the PSTN signals to TCP / IP. RMS reports a significant outbreak call and abnormal operating conditions to administrators. In this study, we developed optimized protocol to PSTN environment that is required by RMS and implemented its differentiated process. And a RAS-RMS Protocol was added to the Application Layer. Development protocol consisting of simple structure as compared to CoAP, MQTT or HTTP can work properly in low-spec CPU and transmit elevator emergency key information easily.

• Journal of Broadcast Engineering
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• v.23 no.5
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• pp.682-692
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• 2018

In this paper, we propose an ARQ packet error control scheme using multiple threads in delivering massive capacity of multimedia based on MMT(MPEG Media Transport) protocol. On the sending side, each frame that constitutes an image is packetized into MMT packets based on MMT protocol. The header of the packet stores the sequence number of the frames contained in the packet and the time of presentation information. The payload of the packet stores the direct information that comprises the frame. The generated MMT packet is transmitted to the IP network. The receiving side checks if any error has occurred in the received packet. For any identified error, it controls the error through ARQ error control scheme and reconfigure the frame according to the information stored in the header of the received packet. At this point, a multi-threading based transport design is constructed so that each thread takes over a single frame, which increases the transmission efficiency of massive capacity multimedia. The efficiency of the multi-threading transport method is verified by solving the problems that might arise when using a single-thread approach if packets with errors are retransmitted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.7-13
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• 2019

Unlike a typical video wall system, video wall systems used for integrated monitoring in smart city environments should be able to display various videos, images, and texts simultaneously. In this paper, we propose an Internet Protocol (IP)-based video wall system that has no limit on the number of videos that can be monitored simultaneously, and that can arrange the monitor screen layout without restrictions. The proposed system is composed of multiple display servers, a wall controller, and video source providers, and they communicate with each other through an IP network. Since the display server receives and decodes the video stream directly from the video source devices, and displays it on the attached monitor screens, more videos can be simultaneously displayed on the entire video wall. When one video is displayed over several screens attached to multiple display servers, only one display server receives the video stream and transmits it to the other display servers by using IP multicast communications, thereby reducing the network load and synchronizing the video frames. Experiments show that as the number of videos increases, a system consisting of more display servers shows better decoding and rendering performance, and there is no performance degradation, even if the display server continues to be expanded.