• ETRI Journal
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• v.24 no.2
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• pp.142-152
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• 2002

In this paper, we propose and analyze a new multiple access protocol for a local area optical Internet based on a wavelength division multiplexing technique which uses a passive star coupler. The proposed contention-based reservation protocol can support variable-length as well as fixed-length messages for transporting Internet packets with one reservation of a minislot at the beginning of a packet transmission. The minislot is used to reserve the data channel on the basis of the slotted ALOHA protocol and the control node ensures subsequent message transmission on the same wavelength. Thus, all messages need not be broken down to many fixed-length packets, and consecutive messages are transmitted through the same wavelength. Moreover, the proposed protocol reduces the collision probability of minislots and improves wavelength utilization. We determine the maximum throughput and verify the results with simulation.

• Structural Engineering and Mechanics
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• v.72 no.3
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• pp.367-382
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• 2019

This paper presents experimental and analytical investigations on additional fixed-end rotations resulting from the strain penetration of high-strength reinforcement in reinforced concrete (RC) beam-column connections under monotonic loading. The experimental part included the test of 18 interior beam-column connections with straight long steel bars and 24 exterior beam-column connections with hooked and headed steel bars. Rebar strains along the anchorage length were recorded at the yielding and ultimate states. Furthermore, a numerical program was developed to study the effect of strain penetration in beam-column connections. The numerical results showed good agreement with the test results. Finally, 87 simulated specimens were designed with various parameters based on the test specimens. The effect of concrete compressive strength ($f_c$), yield strength ($f_y$), diameter ($d_b$), and anchorage length ($l_{ah}$) of the reinforcement in the beam-column connection was examined through a parametric study. The results indicated that additional fixed-end rotations increased with a decrease in $f_c$ and an increase in $f_y$, $d_b$ and $l_{ah}$. Moreover, the growth rate of additional fixed-end rotations at the yielding state was faster than that at the ultimate state when high-strength steel bars were used.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.85-90
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• 1996

In the word, there is varied types of vibration, and these affect the mechanical industry. In this paper is plates with two parallel sides fixed. Electronic speckle pattern interferometry (ESPI) is one of the optical nondestructive testing technique. By using the ESPI, vibration modes for excitation point, a/b(ratio of longuitudinal and lateral length), and kind of specimen are measured and compared qualitatively with theoritical analysis that Warburton proposed.

• Journal of the Korean Mathematical Society
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• v.35 no.3
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• pp.727-740
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• 1998

Controlling traffic lights at a bottleneck, in [5] a time of open passage is called optimal, if it minimizes the first moment of the asymptotic distribution of the queue length. The discussion of the first moment as function of the time of open passage is based on an analysis of the behavior of a fixed point when varying control parameters and delivers theoretical and computational aspects of the traffic problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9B
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• pp.783-792
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• 2003

We consider a finite-buffer discrete-time queueing system with fixed-size bulk-service discipline: Geo/ $G^{B}$1/K＋B. The main purpose of this paper is to present a performance analysis of this system that has a wide range of applications in Asynchronous Transfer Mode (ATM) and other related telecommunication systems. For this purpose, we first derive the departure-epoch probabilities based on the embedded Markov chain method. Next, based on simple rate in and rate out argument, we present stable relationships for the steady-state probabilities of the queue length at different epochs: departure, random, and arrival. Finally, based on these relationships, we present various useful performance measures of interest such as the moments of number of packets in the system at three different epochs and the loss probability. The numerical results are presented for a deterministic service-time distribution - a case that has gained importance in recent years.s.

• Smart Media Journal
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• v.10 no.1
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• pp.16-24
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• 2021

The exiting word embedding methodology such as word2vec represents words, which only occur in the raw training corpus, as a fixed-length vector into a continuous vector space, so when mapping the words incorporated in the raw training corpus into a fixed-length vector in morphologically rich language, out-of-vocabulary (OOV) problem often happens. Even for sentence embedding, when representing the meaning of a sentence as a fixed-length vector by synthesizing word vectors constituting a sentence, OOV words make it challenging to meaningfully represent a sentence into a fixed-length vector. In particular, since the agglutinative language, the Korean has a morphological characteristic to integrate lexical morpheme and grammatical morpheme, handling OOV words is an important factor in improving performance. In this paper, we propose parallel Tri-LSTM sentence embedding that is robust to the OOV problem by extending utilizing the morphological information of words into sentence-level. As a result of the sentiment analysis task with corpus in Korean, we empirically found that the character unit is better than the morpheme unit as an embedding unit for Korean sentence embedding. We achieved 86.17% accuracy on the sentiment analysis task with the parallel bidirectional Tri-LSTM sentence encoder.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1184-1189
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• 2001

In this paper was analyzed the performance of turbo code using semi-random interleaver which proposed a reference numbers 11. Which was analyzed comparison the performance of between the current mobile communication system had been used the viterbe decoding algorithm of convolutional code and turbo codes when fixed constraint length. The result was defined that the performance of turbo code rose a $E_{b/}$ $N_{o}$=4.7[㏈] than convolutional code, when convolutional code and turbo code was fixed by BER = 10$^{-4}$ and constraint length K 5.5.5.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.9-17
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• 1994

ATM (Asynchronous Transfer Mode) has a fixed-length packet transport scheme. It is one of the promising proposals in B-ISDN.Since the packet length is fixed, it can be potentially to perform the various service to users. In this paper, a queueing model for an ATM multip`exer loaded by CBR and ON/OFF input sources is considered, and the two-queue system which each type of input sources has a queue with a finite capacity is analyzed. The cell loss probabilities for a performance measures of ATM multiplexer are derived, and are also evaluated through numerical examples. As a result, the cell loss probability of ON/OFF sources for the queue size is rapidly decreased when the multiplexed number and burstiness are increased. Since cells of the CBR source have lower priority than cells of the ON/OFF source, cell loss probabilities of CBR sources are accordingly high independently of CBR cell arrival rate when the number of CBR sources is large.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.547-549
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• 2014

In RFID systems, the performance for the tag identification is closely related with the tag collision, which is caused by the simultaneous transmission. The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. This algorithm uses the fixed frame size at every scan. Therefore, it is anticipated that the performance of PS algorithm can be variously shown according to the number of tags, frame size, and power level increase. In this paper, we analize the performance of PS algorithm according to the frame length and power level increase.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4324-4342
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• 2014

Previous papers analyzed the throughput performance of the CDMA ALOHA system in Rayleigh fading channel, but they assume that the channel coefficient of Rayleigh fading was the same in the whole packet, which is not realistic. We recently proposed the finite-state Markov channel (FSMC) model to the throughput analysis of DS uncoded CDMA/unslotted ALOHA networks for fixed length data traffic in the mobile environment. We now propose the FSMC model to the throughput analysis of coded DS CDMA/unslotted ALOHA networks with variable length data traffic and one or two user classes in the mobile environment. The proposed DS CDMA/unslotted ALOHA wireless networks for two user classes with access control can maintain maximum throughput for the high priority user class under high message arrival per packet duration.