• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.57-60
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• 1999

In many radio communication environments, there is a special component, called inter-symbol interference (ISI), mused by multipath time delay of signal and ISI components impose limitation of the data transmission rate. In this paper, we consider signaling pulse shapes, called partial response signaling (PRS), for minimizing the effect of ISI and show the improvement of performance by applying one of the partial-response signaling (PRS) pulses to two types of receiver system under dependent noise environments through the Monte-Carlo computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.4
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• pp.285-301
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• 1988

The symbol error rate equations of multi-level quadrature PRS(QPRS) system have been derived in the individual and composite environment of Gaussian/impulsive noise, cochannel CW interference, carrier offset, phase jitter and fading. And using the derived error rate equations, the probability of error has been evaluated and shown in graphs as functions of carrier to noise power ratio, carrier to interference power ratio, phase error, impulsive index, the ration of Gaussian noise to impulsive noise power component, signal to noise power ration in phase locked loop(PLL), and fading figures. The rseults show that the error rate performances are generally more more degraded by impulsive noise than by Gaussian noise. But on the contrary the erors occurred more frequently by Gaussian noise than impulsive noise in a fading environment.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1988.10a
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• pp.195-198
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• 1988

• Journal of Communications and Networks
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• v.5 no.1
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• pp.1-6
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• 2003

In this paper, we extend the derivation of the iterative soft-output Viterbi algorithm (SOVA) for partial response (PR) channels, and modify its decoding process such that it works consistently for arbitrary high code rates, e.g., rate 64/65. We show that the modified SOVA always outperforms the conventional SOVA that appears in the literature with a significant difference for high code rates. It also offers a significant cut down in the trace-back computations. We further examine its performance for parallel and serial concatenated codes on a precoded Class IC partial response (PR4) channel. Code rates of the form $\frac{k_0}{k_0+1}$($k_0$ = 4, 8, and 64) are considered. Our simulations indicate that the loss suffered by the modified SOVA, relative to the APP algorithm, is consistent for all code rates and is at most 1.2 dB for parallel concatenations and at most 1.6 dB for serial concatenations at $P_b$ = $10^{-5}$.

• Journal of IKEEE
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• v.15 no.1
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• pp.70-75
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• 2011

Longitudinal recording has been the cornerstone of all two generations of magnetic recording systems, FDD and HDD. In recent, perpendicular recording has received much attention as promising technology for future high-density recording system Research into signal processing techniques is paramount for the issued storage system and is indispensable like longitudinal recording systems. This paper focuses on the performance evaluation of the various detectors under perpendicular recording system. Parameters for improving the their performance are examined for some detectors. Detectors considered in this work are the partial response maximum likelihood (PRML), noise-predictive maximum likelihood (NPML), fixed delay tree search with decision feedback (FDTS/DF), dual decision feedback equalizer (DDFE) and multilevel decision feedback equalizer (MDFE). Their performances are analyzed in terms of mean squared error (MSE) and noise power spectra, and similarity between recording channel and partial response (PR) channel.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.2
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• pp.63-67
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• 2006

Suppressor of cytokine signaling (SOCS) is known to playa key role as a negative feedback regulator in JAK/STAT signaling cascade in innate immunity. Our laboratory has recently been interested in elucidating the interactions between Spodoptera exigua (Se) and SeNPV. This context leads us to clone and characterize SeSOCS that may have important functions in response to SeNPV infection. Using the RT-PCR and TA cloning approach, we found a partial fragment (416 bp) of SeSOCS. Blast search and multiple alignment data showed that it has a homology to various insects such as Anopheles gambiae (78%), Aedes aegypti (75%), Drosophila melanogastar (77%), Mus musculus (69%), and Homo sapiens (69%). Temporal induction patterns of SeSOCS were analysed after being immune-challenged with either NPV or laminarin. It showed that the level of SeSOCS mRNA was strongly induced in a biphasic manner in response to SeNPV and laminarin, respectively. It seems that SOCS, a negative regulator of JAK/STAT signaling system is also present in S. exigua and may playa role in innate immunity albeit its precise role should be further elucidated at the molecular and cellular level in the early phase of SeNPV infection in larvae.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.1
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• pp.85-93
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• 1997

In this paper, a novel method for obtaining spectra of short pulses is proposed. This method will be well-applied to perform spectral analyses of ultrashort laser pulses which are known to be difficult to evaluate their exact forms in frequency domain because of their narrow-width characteristics in time domain. It must be noted that the method can be represented by a recursive formula derived from the PRS(partial-response signaling) model, and thus more easily available for numerical solutions than the conventional methods such as consecutive differentiations and convolutions. The pulses whose fundamental frames can be exactly determined or approximately represented by truncated Fourier series have well-behaving conditions for applications of this new method. Moreover, the transversal 9-type PRS model can offer various approximations for spectral analyses of ultrashort pulses currently used in transmission systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.597-604
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• 1994

In this paper, the "Stop-and-GO" algorithm is applied to the PRS(Partial Response Signal) type signaling. Stop-and-GO blind equalizer has a property of stopping the adaptation of its tab coefficients by means of a simples flag telling the equalizer whether the current output error with respect to decided symbol is sufficiently reliable to be used. PRS has the rule os level transition, which makes it possible that the level of currently received symbol is in the adjacent levels of the previously received symbol. New nonlinear estimators for PRS, based on the rule of level transition, is proposed. The computer simulation results show the improvement in performance achievable with proposed nonlinear estimators.stimators.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.11
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• pp.83-96
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• 1996

On PR-IV magnetic recording systems, the maximum likelihood sequence detection (MLSD) method is optimum. But it has the problem of the complexity of the structure. The three level detection (TLD) method can be used, which has simpler structure than MLSD, but requires almost twice of power to achieve the same probbility of error as MLSD does. Therefore a new detection method (error controlled detection: ECD) is proposed which has much simpler structure than MLSD and gives much better performance than TLD. The simulation resutls show that the performance of ECD is better than that of TLD by approximaterly 0.5~1.3dB both in linear and nonlinear channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.1
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• pp.11-17
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• 1984

A study is presented showing the effect of carrier phase error on the error-rate of a (Class I, II, IV)PR shaped SQAM digital communication system. A simple upper bound on the probabilty of error as a function of phase error is derived and compared to one another. The results show that the three system can be used appropriately if carrier phase error is less than 3$^{\circ}$. However, if phase error is larger than 3, the PR class I is the best choice.