• The KIPS Transactions:PartD
• /
• v.15D no.5
• /
• pp.609-620
• /
• 2008

The service handling the map data in the mobile device including navigation, LBS, Telematics, and etc., becomes various. The size of map data which is stored and managed in the mobile device is growing and reaches in several GB. The conventional navigation system has used the read-only PSF (physical storage format) in order to enhance the performance of system by maximum in the mobile device which has limited resources. So though a little part of the map data is changed the whole data must be updated. In general, it takes several ten minutes to write the 2 GB map data to a flash memory of mobile device. Therefore, we have developed the mobile spatial DBMS (database management system) to solve the problem which is that the partial map data couldn't be updated in the conventional navigation system. And we suggest the policy to guarantee the performance of the navigation system which is implemented using the spatial mobile DBMS and verify this by experiment.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.8
• /
• pp.1290-1298
• /
• 1989

A new dynamic RAM cell called Trench Epitaxial Transistor Cell (TETC) has been developed for 4M to 16M DRAMS. Also the fabrication process for device isolation which can decrease the narrow effect using SEG process has been developed. We verified the characteristic of the new cell structure with the PICSES simulator on VAX8450.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.8
• /
• pp.41-51
• /
• 1997

The device simulator (BANDIS) which can analyze efficiently the electrical characteristics of the semiconductor devices under the three dimensional stationary conditions on the IBM PC was developed. Poisson, electon and hole continuity equations are discretized y te galerkin method using a tetrahedron as af finite element. The frontal solver which has exquisite data structures and advanced input/output functions is dused for the matrix solver which needs the highest cost in the three dimensional device simulation. The discretization method of the continuity equations used in BANDIS are compared with that of the scharfetter-gummel method used in the commercial three-dimensional device. To verify an accuracy and the efficiency of the discretization method, the simulation results of the PN junction diode and the BJT from BANDIS are compared with those of the commercial three-dimensiional device simulator such as DAVINCI. The maximum relative error within 2% and the average number of iterations needed for the convergence is decreased by more than 20%. The total simulation time of the BJT with 25542 nodes is decreased to about 60% compared with that of DAVINCI.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.30A no.2
• /
• pp.53-63
• /
• 1993

Device degradations by the Fowler-Nordheim tunneling have been studide. The changes of device characteristics such as the threshold voltage, subthreshold slope, I-.or. curves have been measured after bidirectionally stressing n-channel MOSFET's and p-channel MOSFET's. Also the interface states have been directly measured by the charge pumping methodIt is shown that the change of interface states is determined by the number of hole carriers tunneling the gate oxide and electrons which are trapped in the gate oxide. Also, in this paper, we propose a model for device lifetime limited by the increase of interface states.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.4
• /
• pp.129-135
• /
• 1996

In this paper, the hot carrier effect and device degradation of deep submicrometer SC-PMOSFETs have been measured and characterized. It has been shown that the substrate current of a 0.15$\mu$m PMOSFET increases with increasing of impact ionization rate, and the impact ionization rate is a function of the gate length and gate bias voltage. Correlation between gate current and substrate current is investigated within the general framework of the lucky-electron. It is found that the impact ionization rate increases, but the device degradation is not serious with decreasing effective channel length. SCIHE is suggested as the possible phusical mechanism for enhanced impact ionization rate and gate current reduction. Considering the hot carrier induced device degradation, it has been found that the maximum supply voltage is about -2.6V for 0.15$\mu$m PMOSFET.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.5
• /
• pp.90-96
• /
• 2008

This paper presents an algorithm of a single chip acoustic speech enhancement for telematics device. The algorithm consists of two stages, i.e. noise reduction and echo cancellation. An adaptive filter based on cross spectral estimation is used to cancel echo. The external background noise is eliminated and the clear speech is estimated by using MMSE log-spectral magnitude estimation. To be suitable for use in consumer electronics, we also design a low cost, high speed and flexible hardware architecture. The performance of the proposed speech enhancement algorithms were measured both by the signal-to-noise ratio(SNR) and recognition accuracy of an automatic speech recognition(ASR) and yields better results compared with the conventional methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.6
• /
• pp.117-125
• /
• 2012

Recently, there has been a fast paradigm shift in the automotive market from the traditional machine-oriented technology into the technology for vehicle informatics and electronics. In particular, telematics market is accelerating the development of technologies for vehicle informatics through the close cooperation between the vehicle makers and mobile communication companies. However, there may be the degradation of the quality of service by the interference since the telematics uses the wireless communication infrastructure for the base station-to-vehicle communication and the vehicle-to-vehicle communication. This paper presents an analysis device to easily analyze the interference by the wireless communication in the vehicle wireless network environment. Using the analysis results by the presented device, this paper shows that the link quality can be improved through the simulation and the experiment in real environment both.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.7
• /
• pp.230-244
• /
• 1996

We derive analytic expressions for the spontaneous emission spectrum (SES) of a multisection distributed feedback (DFB) structure device employing complex coupled gratings including the effects of both facets reflections. The multisection DFB structure device used in the analysis is a general model which allows the independent phase of a grating in each section, and the sections without gratings. The expressions are the same as those derived by makino and glinski in case the gratings are index coupled and the phase of a grating in each section, ${\varphi}_k$ is '0' which means the phase of gratings in the device is ocntinuous. The expressions for the SES of a phase-shift-controlled (PSC) DFB structure device using tunable devices are derived from the general expressions. The number of parametes of the expressions is reduced by using the parameter of effective phase shift defined by the sum of the phase shift in a PSC region and the difference of the phase of a grating in each active region. Equations showing the effect of both facets reflections and the effective phase shift on the SES are derived. The validaty of the equations is verified by computer simultions. Computer simulation results also show the possibility of evaluating the structure parametes of the device from its SES.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.11
• /
• pp.1706-1711
• /
• 1989

Unit processes for the fabrication of HEMT(high electron mobility transistor)was studied and the optimum conditions of them were applied to the fabrifcation of a discrete HEMT device. The HEMT with a nominal gate-source spacing of 3.6\ulcorner and a gate length of 2.8\ulcorner showed a transconductance of 46.1mS/mm and a threshold voltage of -0.29V. A source-drain voltage of 2.0V for a saturation current of 35mA/mm was achieved.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.7
• /
• pp.127-133
• /
• 1996

In this paper, we propose a new fabrication method for poly-Si TFTs with a self-aligned offset gated structure by employing a photoresist reflow process. Compared with the conventional poly-Si TFTs, the device is consist of two gate electrodes, of which one is the entitled main gate where the gate bias is employed and the other is the entitled subgate which is separate form both sides of the main gate. The poly-Si channel layer below the offset oxide is protected form the injected ion impurities for the source/drain implantation and acts as an offset region of the proposed device. The key feature of oru new device is the offset region due to the offset oxide. our experimental reuslts show that the offset region, due to the photoresist reflow process, has been sucessfully obtained in order to fabricate the offset gated poly-Si TFTs. The maximum ON/OFF ratio occurs at the L$_{off}$ of 1.1${\mu}$m and exceeds 1X10$^{6}$.