• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.11A
• /
• pp.1072-1078
• /
• 2008

In this paper, we propose an efficient superposition coding multiplexing(SCM) method based on power allocation in descending order for fading broadcast channels in which per-user minimum and maximum rate constraints are considered in order to maximize the transmission effectiveness. It consists of three steps as follows. In the first step, a user group is selected to maximize the number of users with whom a transmitter can communicate instantaneously. In the second step, per-user power allocation for each user is done in descending order of transmit power by determining a maximum allowable interference power from all subsequent interfering users in order to guarantee its corresponding minimum rate, and then a residual power is calculated. The final step is performed if some power remains even after the second step. In this step, additional power allocation is performed up to the maximum transmit power to provide the maximum rate to the corresponding user, again in ascending order, starting from the last user in descending order. But, this method does not require power reallocation to subsequent users because tentative power allocation in the second step has been performed in descending order to guarantee the minimum rate for each user, taking into account the maximum allowable interference power from all the subsequent users. Therefore, the proposed method gets more efficient in term of computational complexity when per-user minimum as well as maximum rate constraints exist, especially as the number of users increases.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.12
• /
• pp.2641-2646
• /
• 2009

The more growing on home automation system at automatic control, the more efficiency required for energy consumption and for recycling energy in near future. Heating is essential in general apartment. Heating method is two types in apartment. One uses electricity, and other one uses warm water. If use electricity, is not efficient by rise of electric charges. But, It can reduce much in expense aspect, if use warm water. When use warm water, temperature of warm water is not equal from all pipe parts. Therefore, indoor tempera can be unequal with set point. Solution of these problems is as following. Temperature sensor in warm water attach pipe. The measured temperature transmits by real time. Temperature of warm water controls in receiver side. In this paper, we propose an automatic temperature transmission system for the heating pipe at home, that is a low-power based, and supply the energy source from a small AC motor resided in bottom cement mortal. The proposed system is used in power mechanism from a collision process of water-jet using propeller water-difference and also designed a CPU module by Atmega8 at ATMEL co., Inc. and a communication module by CC1020 at Chipcon co., Inc.

• Journal of the Society of Disaster Information
• /
• v.20 no.1
• /
• pp.206-212
• /
• 2024

Purpose: This study conducted research on the sharing of information to enhance the survival rate of emergency patients by swiftly transferring them to appropriate hospitals through sharing the patients' conditions, treatment histories, and transportation information with the Maritime Police Agency and relevant agencies when emergencies occur in the marine environment. Methods: In this study, emergency patient information classified in a smartphone app was received, stored, and transmitted using the LoRa communication method by electronic triage tags, and the transmitted emergency patient information was implemented to be collected in real-time through a hybrid triage system along with LoRa receivers. Results: Through the hybrid triage system, it was possible to receive emergency patient information according to the distance or confirm delayed reception. It was observed that most data were received when the distance was short, while data reception was unsuccessful in relatively longer distances. Conclusion: It was confirmed that in mass disaster environments where internet communication is impossible, rapid and accurate understanding of casualty information at disaster sites and appropriate disaster responses can be achieved using self-networking methods such as LoRa communication. However, limitations inherent in communication methods were also recognized. Further research on various communication methods is required to collect emergency patient information and transfer them to appropriate hospitals in situations where internet communication is unavailable.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.1
• /
• pp.48-59
• /
• 2009

Next generation mobile communication system will have various access networks and provide seamless multimedia data service to mobile nodes. The WiNGS system, one of these access network, has superior RAT(Radio Access Technology) and network connectivity other than previous ones. In this paper, we propose link-layer SR-ARQ between mobile node and WAGW to solve packet re-ordering problem during handover. In the proposed scheme, we apply the adaptive timer at the SR-ARQ sender to reduce unnecessary packet retransmission during handoff and delayed NAK algorithm at the SR-ARQ receiver for delaying NAK response due to temporary out-of-sequenced frames. We evaluate the performance of the proposed scheme by implementing the new SR-ARQ protocol at the link-layer using ns-2 simulator, and show the handover performance is improved greatly by preventing unnecessary retransmission.

• (The) Research of the performance art and culture
• /
• no.18
• /
• pp.563-598
• /
• 2009

Gangneung Danoje is a local festival that has its origin in the county festival handed down premodern society. It was designated as an important intangible cultural asset in 1966, and has appreciated as a representative traditional festival of Korea since UNESCO designated it as 'the Oral and Intangible Heritage of Humanity' in 2005. Generally, it is known as a festival which it keeps up the premodern tradition. However, we can know that it is different from the festival performed in the 19 century in its framework and contents if we pay attention to the texts of festival performed in Gangneung today. I think that this change is a result of cultural adaptation by the change of transmission situation, and especially today texts of festival is an result of the pursuit, restoration and reproduction of its traditional form so as to be designated as a cultural asset. In this paper, after I have an accurate grasp of the traditional form of Gangneung Danoje from the present data related to Gangneung Danoje, I will compare its traditional text with the existing text which was reconstructed at the time of being designated as an important intangible cultural asset. To do this work, I verified the composition method of a county festival by investigating a general aspect of county festival in the $Chos{\breve{o}}n$ dynasty, brought out the aspect of its change by comparing its existing text with the procedures and contents of Gangneung Danoje before the Japanese occupation by force, and discussed the matter of its some changes. As a result of my work, I ascertained that the present Gangneung Danoje is very different from the festival transmitted in premodern society in the structure, time and space of festival, and the contents of performance containing the procedures of meeting god, seeing god off, and enjoying god.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.2A
• /
• pp.143-151
• /
• 2007

One of the consideration things to design protocol in wireless sensor networks is to maximize lifetime of sensor node as reducing energy consumption. In this paper propose reserve based multichannel CSMA mac protocol for minimizing energy consumption which arise from collision and waiting retransmission at channel access process in mac layer Each sensor node which constitute sensor networks has data channel and control channel. And as sensor node reserve channel for data transmission by using control channel and receipt node allow reservation node to use data channel, sending node can abbreviate try of retransmission after random interval time. Also, When sending node delivers selects option channel in available channels to receipt node, the receipt node decide whether the channel is available to oneself and through the result select transmission channel ultimately. Performance evaluation compare with previous simple multichannel CSMA.

• The Journal of the Acoustical Society of Korea
• /
• v.33 no.4
• /
• pp.262-267
• /
• 2014

Recently, long pulses are transmitted for target detection in active sonar application. Matched filtering implemented by simple convolution algorithm, requires massive computational power for long replica. The computational loads are reduced significantly by implementing the convolution in the frequency domain with overlap add method, but the performance degrades for specified input/output system delay which constrains the size of FFT function. For performance improvement, the replica could be partitioned into uniform blocks (FDL) by re-using IFFT operations, or variable blocks of increasing length (MC) by using the largest possible blocks to calculate the convolution. In this paper, by combining the strong points of the two methods, we propose a new filter partition structure that allows for further optimization of the previous two methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.10
• /
• pp.941-950
• /
• 2011

In this paper, we analysis the end-to-end performance of the incremental cooperative communication with relay selection. In the conventional cooperative scheme, the source(S) broadcasts the signal to the relay(R) and the destination(D) at 1st phase, and the R forwards the signal to the D at 2nd phase. Although this scheme can improve performance and provide diversity gain, it suffers from decreasing spectrum efficiency. In order to overcome this problem, the incremental cooperative model can be used. In this paper, we study two incremental cooperative method : the first uses ARQ with threshold SNR and the second uses HARQ with channel coding. we also evaluated performance of the incremental cooperative communication based on the R arrangement by using both methods.

• Composites Research
• /
• v.14 no.5
• /
• pp.12-19
• /
• 2001

In aircraft composite structures, structural defects such as matrix cracks, delaminations and fiber breakages are hard to detect if they are breaking out in operating condition. Therefore, to assure the structural integrity, it is desirable to perform the real-time health monitoring of the structures. In this study, a fiber optic sensor was applied to the composite beams to monitor failure and strain in real-time. To detect the failure signal and strain simultaneously, laser diode and ASE broadband source were applied in a single EFPI sensor using wavelength division multiplexer. Short time courier transform and wavelet transform were used to characterize the failure signal and to determine the moment of failure. And the strain measured by AEFPI was compared with the that of strain gage. From the result of the tensile test, strain measured by the AEFPI agreed with the value of electric strain gage and the failure detection system could detect the moment of failure with high sensitivity to recognize the onset of micro-crack failure signal.

• Journal of Internet Computing and Services
• /
• v.3 no.4
• /
• pp.11-18
• /
• 2002

The IP multicasting service system based on IGMP(Internet Group Management Protocol) is the receiver initiated multicasting system that all receivers must join to and leave from the server of multicasting service. The IGMP is less effective and reliable to apply the education system that all computers of students ore synchronized a teacher's computer. A proposed middle-ware in this paper provides the reliable data transferring and the server initiated multicasting system that client as student's PC is controled by a multicasting server as teacher's PC, This middle-ware is consisted with two major component, The one is the group manager that handle the status informations of members in each group. Another is the reliable sender/receiver that has The transmission protocol based on NAK message and flow control. As the results of the test that 22khz digital voice data and 1024$\times$768 24bit color image data were tested for 30 PCs connected with 100baseT, the voice data was completely without error transferred and the image data was successfully transferred with 0.004% retransmit rate under 2 frames/sec load.