• Journal of Satellite, Information and Communications
• /
• v.8 no.3
• /
• pp.15-19
• /
• 2013

Lithium-ion batteries have been used for high density energy storage system due to the features such as low self-discharge rate. And the unit cell battery with the voltage less than 4V is recommended to use the series connections for a high voltage charger. When batteries are charged or discharged with series connection, there may be an explosion or degradation of unit cell battery owing to undistributed internal resistance of cell battery. therefore, the voltages of unit cell batteries should be monitored to prevent an overcharging and a deep discharging. This paper introduces the implementation of CVM (Cell Voltage Monitoring) system that can transmit the 12 channel's information including voltages and temperatures with the 12-bits resolutions and the transmission speed of 192 kbps.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37B no.9
• /
• pp.814-821
• /
• 2012

We propose a network processor called an OmniFlow processor capable of wire-speed flow management by a hardware-based flow admission control(FAC) in this paper. Because the OmniFlow processor can set up and release a wire-speed connection for flows, the update period of flows can be set to a short time, and only active flows can be effectively managed by terminating a flow that does not have a packet transmitted within this period. Therefore, the FAC can be used to provide a reliable transmission of UDP as well as TCP applications. This processor is fabricated in 65nm CMOS technology, and total gate count is 25 million. It has 40 Gb/s throughput performance in using the 32 RISC cores when maximum operating frequency is 555MHz.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.7
• /
• pp.8-17
• /
• 2010

Ubiquitous home refers not only to home but also to logical space, including a wide range of out-home personal devices such as mobile phones, PDAs, laptops, car navigators, and office PCs. There are certain connection barriers among the devices, such as the dynamic IP address, NAT. In a home network, various devices coexist in heterogeneous networks, such as IP, IEEE1394, PLC, Bluetooth, ZigBee, UWB, and IrDA, all of which lack interoperability due to their different physical transmission characteristics and protocols. In ubiquitous home where an unrestricted collaboration of the devices is essential to offer services that meet the users' requirements, free interoperability among the devices must be guaranteed. This paper proposes a networking model for interoperability of the heterogeneous devices in a ubiquitous home based on a virtual overlay network which hides the complicated physical network configurations and heterogeneity of the service protocols.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.3
• /
• pp.506-515
• /
• 2015

In this paper, we propose a group playback synchronization method using adaptive synchronization delay time by the bit rate of media to synchronize a play position of streaming media between mobile smart devices. This method consists of streaming server-side and client-side synchronization algorithms based on synchronization delay time which includes connection time, control packet transmission time, streaming data buffering time, and synchronization processing time. We implement the Android media player application with synchronization support using the proposed algorithms and present the result of performance evaluation.

• Journal of Digital Convergence
• /
• v.20 no.1
• /
• pp.185-190
• /
• 2022

Bluetooth is a common wireless technology that is widely used as a connection medium between various consumer electronic devices. The Bluetooth receiver usually adopts a Viterbi algorithm to improve signal-to-noise ratio performance, but requires complex hardware and calculations for continuous search and estimation for the irrational modulation indexes at the transmission. This paper proposes a non-coherent maximum estimation based 8-State Viterbi FSM to solve these complexity problems. The proposed optimal Viterbi FSM can detect Gaussian frequency-shfit keying symbol without any prior information and estimation for the modulation indexes. The HV1/HV2 packets are used for the estimation of the proposed algorithm and the simulation results have shown performance improvements with about 2dB for 10^-3 BER compared to other ideal approaches such as decision direct method.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.1
• /
• pp.53-64
• /
• 2024

The Yeongnam southeastern region, with Ulsan as its focal point, is planning large-scale floating offshore wind power projects. Additionally, due to the establishment of new nuclear power plants and the extension of existing ones, there is a demand for the expansion of the power grid. The government has announced plans to establish a new power grid for this region as part of the 10th power supply plan. However, there are anticipated challenges in the actual construction phase, primarily because of the presence of national parks and cultural heritage protection zones near Gyeongju. As a result, this study presents an alternative approach that minimizes the creation of new power lines by utilizing existing ones. Using the Power System Simulator for Engineers (PSS/E), an analysis of transient stability was conducted and demonstrated its feasibility.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.13 no.2
• /
• pp.148-153
• /
• 2003

A DoS(Denial of Service) attack appears in the form of the intrusion attempt and Syn Flooding attack is a typical example. The Syn Flooding attack takes advantage of the weak point of 3-way handshake between the end-points of TCP which is the connection-oriented transmission service and has the reliability This paper proposes a NIIP(Network based Intelligent Intrusion Prevention) model. This model captures and analyzes the packet informations for the detection of Syn Flooding attack. Using the result of analysis of decision module, the decision module, which utilizes FCM(Fuzzy Cognitive Maps), measures the degree of danger of the DoS and trains the response module to deal with attacks. This model is a network based intelligent intrusion prevention model that reduces or prevents the danger of Syn Flooding attack.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.5
• /
• pp.1320-1332
• /
• 1998

We propose Multiph which is a virtual topology for a reliable group communication platform on dynamic high speed network. We also define group communication primitives for transmission of messages and group management. Multiph consists of a set of nodes which are process groups and a set of edges which are the connection between nodes providing the route of messages. Processes can send and receive messages overlapped in a several multicast groups. Overlapped process organizes non-overlapped logical group, which called meta-group. Multiph guarantees ordering of messages that received at the destination group. It has no extra node that decreases system performance. Although the group has dynamic group change to leave and add process, it does not reconstruct the existing platform structure.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.2
• /
• pp.1-5
• /
• 2011

For measuring quad-band module system using WiBro network, frequency converter was developed. The size of the fabricated frequency converter is $3.1cm{\times}3.1cm{\times}0.4cm$. Noise figure of the receiver part of the frequency converter was 2.62 ~ 3.45 dB, EVM of that is -37.5 dB ~ -34.5 dB. And EVM of the transmission part was -42.5 ~ -35.5 dB. Quad-band module was fabricated with the developed frequency converter. Testing the quad-band module in 2.3 GHz WiBro network results the excellent internet connection for 2.5 GHz, 3.5 GHz and 5.5 GHz band.

• Journal of KIISE:Information Networking
• /
• v.32 no.2
• /
• pp.215-219
• /
• 2005

Generally, the mobile nodes in MANET have the limited power capacity available for actual communications. Thus, the power management is very important for packet routing or forwarding. Although MTPR, MBCR and MMBCR are proposed to treat the problem of power consumption, there have been few researches resolving the link breakdown that is occurred by the power exhaustion during transmission. In this sense, the reliable scheme should be required to ensure the routing connectivity. In this paper, we propose three schemes to enforce the routing connectivity. If the signal strength is dropped below a signal threshold, the candidate route is previously selected to prepare the link breakdown. Also, on multi-channel, we propose the lifetime increment scheme of a node that it manage its available power to the needed power of a new link. The simulation results show the enforcement of the link connectivity and the performance improvements of the delay time through the effective connection management.