• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.48 no.12
• /
• pp.15-22
• /
• 2011

Integrated-optic symmetric/asymmetric Mach-Zehnder interferometers at $1.3{\mu}m$ wavelength were studied as sensing part for electric-field measurement system. The devices were simulated based on the BPM software and fabricated utilizing Ti-diffused $LiNbO_3$ channel optical waveguides and lumped-type electrodes. A half-wave voltage of $V_{\pi}$=6.6V and modulation depth of 100% and 75% for a symmetric structure were measured for 200Hz and 1kHz electrical signal bandwidth, respectively. By the way, almost half-maximum power transmission was observed for asymmetric interferometers with ${\pi}$/2 intrinsic phase difference. Expected experimental measurements were observed for 1kHz electrical signal bandwidth.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.11
• /
• pp.91-99
• /
• 1998

A 5Gbps LiNbO$_3$ optical phase modulator was designed, packaged and it's properties were characterized for optical communications. The APE(annealed proton exchange) method was employed for the optical waveguide and the electrode of ACPS (asymmetric coplanar strip) type was formed by electro-plating on LiNbO$_3$ for applying microwave signal with a dimension of width 18${\mu}{\textrm}{m}$, gap 9${\mu}{\textrm}{m}$ and length 50mm. The fabricated single-moded modulator operated at a 1550nm wavelength exhibits its modulation bandwidth, insertion loss and driving voltage of 7㎓, 3.0dB and 6V, respectively.

• Journal of Advanced Navigation Technology
• /
• v.17 no.2
• /
• pp.177-182
• /
• 2013

In this paper, printed antenna which can be applied to a built-in wireless module of the security controller operating at global positioning system(GPS) L1 frequency band(1.575GHz) is proposed. The proposed antenna is basically composed of a microstrip patch antenna with inserting feed. In particular left and right slots which are respectively asymmetric are used for impedance matching, whereas slot with one open-end and shorting point are used on the bottom plane to set operating frequency and enhance bandwidth. It is observed at the desired GPS L1 frequency band that the radiation efficiency and gain of the proposed antenna are 90% and more than 4.8dBi respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.6
• /
• pp.1689-1706
• /
• 2012

The preservation of temporal dependencies among a group of processes that exchange continuous media at runtime is a key issue for emerging mobile distributed systems (MDS), such as monitoring of biosignals and interactive multiuser games. Although several works are oriented to satisfy temporal dependencies, most of them are not suitable for MDSs. In general, an MDS is characterized by the absence of global references (e.g. shared memory and wall clock), host mobility, limited processing and storage capabilities in mobile hosts, and limited bandwidth on wireless communication channels. This paper proposes an asymmetric synchronization protocol to be used at runtime in an MDS without using a common reference. One main aspect of our synchronization protocol is that it translates temporal constraints to causal dependencies of the continuous media data as seen by the mobile hosts. We simulate the protocol by considering a cellular network environment and by using MPEG-4 encoders. The simulation results show that our protocol is effective in reducing the synchronization error. In addition, the protocol is efficient in terms of processing and storage costs at the mobile devices, as well as in the overhead attached per message across the wired and wireless channels.

• Journal of electromagnetic engineering and science
• /
• v.17 no.2
• /
• pp.57-64
• /
• 2017

In this paper, an asymmetric compact multiband slot antenna is proposed for global positioning system (GPS), worldwide interoperability for microwave access (WiMAX), and wireless area network (WLAN) applications. The top plane, a ground is composed of a rectangular slot with a trapezoidal-like stub, an inverted U-shaped slot at the right side of the rectangular slot, an inverted L-shaped slot at the left side of the rectangular slot, and three stubs. The proposed antenna is fed by an asymmetric cross-parasitic strip on the bottom plane. By properly designing the slots and stubs, four resonant frequency bands are achieved with -10 dB reflection coefficient bandwidths of 50 MHz, 400 MHz, 390 MHz, and 830 MHz in the 1.57 GHz GPS band, 2.4 GHz WLAN band, 3.5 GHz WiMAX band, and 5.5 GHz WLAN bands, respectively. The antenna has a total compact size of $13mm{\times}32mm{\times}0.8mm$. Simulated and measured results indicate that the proposed antenna has sufficient bandwidth and good radiation performance in each band.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.8C
• /
• pp.819-827
• /
• 2002

Personal mobile communication has been developed up to IMT-2000 which is called the third generation mobile communication. The first generation of personal mobile communication was analog cellular, the second was digital cellular, and the 2.5 generation was PCS. Before the third generation had been developed, the personal mobile communication service was focused mainly on the voice-oriented service. But, we can expect that multimedia service after the third generation system will be the core of the subject. T In this thesis, we propose a dynamic resource allocation algorithm in the UTRA TDD systems which can support the asymmetric traffic propensity and multimedia traffic. The proposed algorithm consists two sub-algorithms. One is the dynamic channel allocation method that determines the amount of bandwidth assigned between uplink and downlink according to resource allocation status list through asymmetric traffic propensity. The other is the channel access mechanism that assigns RU to bearer service generated in a cell. By simulation, the proposed dynamic resource allocation algorithm is proved to support asymmetric propensity of traffic and shows a better throughput for multimedia traffic.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.1
• /
• pp.85-91
• /
• 2010

In this paper, a new microstrip antenna using asymmetric U-shaped slotted ground is proposed for a switchable circular polarization sense. The proposed antenna is achieved a circularly polarization from orthogonal E-field distributions with 90 degree phase difference due to the asymmetrical U-shaped slot. Moreover, the circular polarization sense of the proposed antenna can be easily switchable with changing the symmetric plane of the U-shaped slots. As a result, the proposed antenna is implemented by two PIN diodes with two different bias condition for ON/OFF states. The measured axial ratios are about 1.5 dB without the dependence of the polarization sense and 3-dB axial ratio bandwidth are achieved 29 MHz with respect to about 1.2 % at 2.46 GHz operating frequency.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.165-172
• /
• 2012

Integrated-optic asymmetric Mach-Zehnder interferometer at $1.3{\mu}m$ wavelength and segmented electrode structure were designed and fabricated as a sensing part for the electric-field measurement system. The device was simulated based on the BPM software and fabricated utilizing Ti-diffused $LiNbO_3$ channel optical waveguides and lumped-type electrodes. Almost half-maximum power transmission was observed for asymmetric interferometers with ${\pi}/2$ intrinsic phase difference. Expected experimental measurements were observed for 1KHz electrical signal bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.6
• /
• pp.726-732
• /
• 2019

In this study, we proposed an asymmetric differential inductor to improve the linearity of differential power amplifiers. Considering the phase error between differential signals of the differential amplifier, the location of the center tap of the differential inductor was modified to minimize the error. As a result, the center tap was positioned asymmetrically inside the differential inductor. With the asymmetric differential inductor, the AM-to-AM and AM-to-PM distortions of the amplifier were suppressed. To confirm the feasibility of the inductor, we designed a 2.4 GHz differential CMOS PA for IEEE 802.11n WLAN applications with a 64-quadrature amplitude modulation (QAM), 9.6 dB peak-to-average power ratio (PAPR), and a bandwidth of 20 MHz. The designed power amplifier was fabricated using the 180-nm RF CMOS process. The measured maximum linear output power was 17 dBm, whereas EVM was 5%.

• Journal of Digital Convergence
• /
• v.19 no.3
• /
• pp.211-216
• /
• 2021

Information from various heterogeneous devices is steadily increasing in distributed cloud environments. This is because high-speed network speeds and high-capacity multimedia data are being used. However, research is still underway on how to minimize information errors in big data sent and received by heterogeneous devices. In this paper, we propose a deep learning-based asymmetric storage management technique for minimizing bandwidth and data errors in networks generated by information sent and received in cloud environments. The proposed technique applies deep learning techniques to optimize the load balance after asymmetric hash of the big data information generated by each device. The proposed technique is characterized by allowing errors in big data collected from each device, while also ensuring the connectivity of big data by grouping big data into groups of clusters of dogs. In particular, the proposed technique minimizes information errors when storing and managing big data asymmetrically because it used a loss function that extracted similar values between big data as seeds.