• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.32-40
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• 2011

Reversible data hiding, which can recover the original image without any distortion after the extraction of the hidden data, has drawn considerable attention in recent years. However, underflow and overflow problems have occurred occasionally in the embedded image. To overcome these problems, we propose a new reversible data hiding algorithm which embeds a compressed location map used to identify these underflow and overflow points. In addition, the proposed algorithm allows for multilevel data hiding to increase the hiding capacity. The simulation results demonstrate that the proposed algorithm generates good performances in the PSNR, the embedding capacity, and the size of side information.

• Journal of Korea Water Resources Association
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• v.44 no.12
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• pp.955-965
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• 2011

The flow characteristics of rectangular and 1 : 1 and 1 : 2 trapezoidal weirs were investigated through hydraulic experiments in order calculate the exact overflow discharge of the broad-crested side weir. The flow was found to be most stable in trapezoidal shapes with the lowest incline. The 1 : 1 and 1 : 2 trapezoidal weirs had 5.67% and 8.57% increases, respectively, compared to the rectangular weir in terms of overflow amount, which suggests that they are more effective in preventing flood. An integrated discharge coefficient equation taking into account the discharge coefficient equation and shapes was proposed through a multiple linear regression analysis with an addition of a new parameter for the side wear, $L/L_H$, to the conventional discharge coefficient equation. Also, the applicability of the newly proposed discharge coefficient equation was reviewed by comparing the measured and calculated overflow amounts based on the experimental data of preceding researches and existing researchers and the research data of this study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.1-10
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• 1992

In the already presented paper, the performance analysis of SMUX was need a lot of time bacause of recussive method, So this paper proposed the new mathematical method for the SMUX's performance. And it is constructed and analyzed the queueing model for SMUX based on the Go-back N retransmission ARQ model. It is assumed that it has the infinite buffer and a single server. It is analzied the parameters that have influence on the byffer and a single server. It is analzied the parameters that have influence on the buffer behaviour of statistical multiplexer overflow probabilities. maximum buffer size. mean wating time and mean buffer size, and these relationship are represented the graphs and datas which provided a guide to the buffer design problem. As these results. it is efficient when the SMUX is apphed that the traffic density is below 0.5 and transmission error probabilities is below 10­$^3$. So this paper can be applied to the basic and theoretical background prior to the implementation of SMUX.

• Journal of Digital Contents Society
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• v.16 no.3
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• pp.381-388
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• 2015

TCP, which performs congestion control in congestion condition, is able to help a reliable transmission. However, packet loss can be increased because congestion window is increased by the time the packet is dropped in the process of congestion avoidance. In this paper, to solve the above problem, we propose a new congestion estimation based TCP congestion control scheme using the weighted average value of the RTT. After measuring a SRTT, which means the weighted average value of RTTs, at this point of time when a buffer overflow is occurred by an overloaded packet, the proposed scheme estimates the time, when the same SRTT is made in packet transmission, as a congestion time and then decreases the congestion window. The simulation results show that the proposed schem has a good performance in terms of packet loss rate and throughput when the packet loss due to buffer overflow is larger than that due to wireless channel.

• Journal of Digital Contents Society
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• v.17 no.3
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• pp.181-188
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• 2016

Video streaming traffics which are arrived in receiver have irregular traffic patterns by many problems over the network path. Particularly, if these received traffics enter into replay buffer without any operation, the overflow and underflow effects are made according to the buffer status. There was an existing scheme which automatically set up token bucket parameters using the video information file under the assumption of the lossless packet on network. The existing scheme has a problem which can set up the wrong token bucket parameters by the lost packets on the practical networks with video packet loss. Therefore, this paper proposes a new scheme which reset up video file information to correct the wrong token bucket parameters in case of packet loss in practical networks with packet loss. Through the simulation, it was found that the proposed scheme would have better performance than the existing scheme in terms of overflow generation and packet loss.

• Journal of Korea Water Resources Association
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• v.53 no.6
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• pp.451-461
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• 2020

Urban flooding due to rapid urbanization has recently become frequent. In this study, a hydraulic model experiment was conducted on Shinwol rainwater storage and drainage system constructed for the first time in South Korea to prevent urban flooding. Experiments were preformed for 55 scenarios, of which 19 overflows occurred. In addition, the video analysis for the scenarios where the overflow occurred showd that the overflow occurred during the process of exhausting the pressurized air in the facility and the undular bore were moving. Results of this study, it was judge that it would be advantageous to maintain a completely drained or full-pipe condition for stable operation of the Shinwol rainwater storage and drainage system for continuous rainfall in the future. And it is necessary to additional research on the correlation for the magnitude of inflow discharge, overflow and undular bore.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1571-1582
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• 2016

One of the issues, which is dealed with in undirectional data transmission technology, is reducing the packet loss in TCP based data transfer. We can decrease the packet loss by using several well known error correction approaches. Although we utilize those previous approaches, the packet loss by both link errror and buffer overflow could be occurred. In this paper, we propose the RED(REliable Data diode). RED also uses the TCP proxy approach for supporting the TCP based data transfer which is similar with the existing unidirectional data transmission technologies. The RED transmission system could alleviate the packet loss caused by buffer overflow by exploiting the delaying transmission of TCP packets. Furthermore, in order to reduce the packett loss caused by link error in the unidirectional transmission link, the RED transmission system transmits one or more duplicated packets to the RED reception system by considering both the remaining resources and packet importance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.812-821
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• 2009

This paper proposes a novel dynamically reconfigurable switch for various multimedia applications in hybrid NoC systems. Current NoC systems, which adopt hybrid NoC structure with fixed switch and job distribution algorithms, require designers to precisely predict the property of applications to be processed. This paper proposes a reconfigurable switch which minimizes buffer overflow in various multimedia applications running on an NoC system. To verify the performance of the proposed system, we performed experiments on various multimedia applications running on embedded systems, such as MPEG4 and MP3 decoder, GPS positioning system, and OFDM demodulator. Experimental results show that buffer overflow has been decreased by 41.8% and 29.0%, respectively, when compared with NoC systems having sub-clusters with mesh or star topology. Power usage has been increased by 2.3% compared with hybrid NoC systems using fixed switches, and chip area has been increased from -0.6% to 5.7% depending on sub-cluster topology.

• Journal of Environmental Impact Assessment
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• v.19 no.2
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• pp.153-168
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• 2010

The objectives of this study are to analyze flow characteristics for a side weir, which is an inlet structure for flow discharge reduction in the main channel through 3 dimensional numerical analysis and to understand the efficiency of the overflow effect at the side weir. In this study over 40 simulations using FLOW-3D, a computational fluid dynamics program were conducted, and the results were analyzed to find the influence of the flow hydraulics, geometry, channel and weir shapes on the coefficient. It is especially considered the relatively high stage in downstream that may cause flow within channel to be backed up along the channel. Additionally by setting up the scale of simulations much larger than the existing test equipment designed by other researchers, it is intended to analyze more accurate hydraulic behavior along with the realistic hydraulic features such as structures and volumes of flow. The results show that for design with subcritical flow only if the Froude number of upstream is sustained below 0.5 and the length of weir is 33-100% of the width of channel, it is expected to improve the efficiency of the overflow over a side weir.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.316-328
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• 2003

In this paper, we propose and analyze two adaptive channel allocation schemes for supporting multimedia traffics in hierarchical cellular systems. It is guaranteed to satisfy the required quality of service of multimedia traffics according to their characteristics such as a mobile velocity for voice calls and a delay tolerance for multimedia calls. In the scheme 1, only slow-speed voice calls are allowed to overflow from macrocell to microcell and only adaptive multimedia calls can overflow from microcell to macrocell after reducing its bandwidth to the minimum channel bandwidth. In the scheme II, in addition to the first scheme, non-adaptive multimedia calls can occupy the required channel bandwidth through reducing the channel bandwidth of adaptive multimedia calls. The proposed scheme I is analyzed using 2-dimensional Markov model. Through computer simulations, the analysis model and the proposed schemes are compared with the fixed system and two previous studies. In the simulation result, it is shown that the proposed schemes yield a significant improvement in terms of the forced termination probability of handoff calls and the efficiency of channel usage.