• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권4호
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• pp.1317-1341
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• 2021

Nowadays, the Internet of Things (IoT) is adopted to enable effective and smooth communication among different networks. In some specific application, the Wireless Sensor Networks (WSN) are used in IoT to gather peculiar data without the interaction of human. The WSNs are self-organizing in nature, so it mostly prefer multi-hop data forwarding. Thus to achieve better communication, a cross-layer routing strategy is preferred. In the cross-layer routing strategy, the routing processed through three layers such as transport, data link, and physical layer. Even though effective communication achieved via a cross-layer routing strategy, energy is another constraint in WSN assisted IoT. Cluster-based communication is one of the most used strategies for effectively preserving energy in WSN routing. This paper proposes a Bio-inspired cross-layer routing (BiHCLR) protocol to achieve effective and energy preserving routing in WSN assisted IoT. Initially, the deployed sensor nodes are arranged in the form of a grid as per the grid-based routing strategy. Then to enable energy preservation in BiHCLR, the fuzzy logic approach is executed to select the Cluster Head (CH) for every cell of the grid. Then a hybrid bio-inspired algorithm is used to select the routing path. The hybrid algorithm combines moth search and Salp Swarm optimization techniques. The performance of the proposed BiHCLR is evaluated based on the Quality of Service (QoS) analysis in terms of Packet loss, error bit rate, transmission delay, lifetime of network, buffer occupancy and throughput. Then these performances are validated based on comparison with conventional routing strategies like Fuzzy-rule-based Energy Efficient Clustering and Immune-Inspired Routing (FEEC-IIR), Neuro-Fuzzy- Emperor Penguin Optimization (NF-EPO), Fuzzy Reinforcement Learning-based Data Gathering (FRLDG) and Hierarchical Energy Efficient Data gathering (HEED). Ultimately the performance of the proposed BiHCLR outperforms all other conventional techniques.

• 한국지역사회생활과학회지
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• 제23권4호
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• pp.467-478
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• 2012

This study was carried out to develop nutrition education materials for nutrient intake and the prevention of disease for the elderly and to test their effects on the health-related matters and nutrition intakes after nutrition education. The mean age of the subjects was 71.6 years old. Diet adjustment for health increased a little bit from 2.2% to 11.1% after education but with no significance. The highest reported chronic illness was hypertension. The drinking of the subjects decreased a little bit after their education but wasn't significant. There were no significant changes to the frequency of food consumption across all the items after education, but there was a small increase to the daily intake of milk and dairy products and fruits and to a balanced diet three times per day. There was a significant increase in the intake of such nutrients as energy(p<0.05), protein(p<0.01), lipid(p<0.05), phosphorus(p<0.05), sodium (p<0.05), vitamin $B_2$(p<0.05), vitamin $B_6$(p<0.05), and niacin(p<0.001) after education. Those findings show that nutrition education provided to the elderly had no clear effects on the items that required memorization such as nutrition knowledge but did have some effects on dietary life. If the nutrition education requiring memorization is provided repeatedly with data supplemented, more effective nutrition management will be possible.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.336-339
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• 2003

A digital data logging system has been developed for the purpose of a compact offline Ocean Bottom Seismometer(OBS). The Digital Data Logger(DDL) consists of A/D system, Micom with storage memory and firmware managing data files. The A/D system acquires data of 16bit/4ch with sampling rate of 250Hz per channel. The Micom, a micro controller board with T33521 processor of 8051 class, was equipped with 8 flash memories of 128MB for data storage capacity of 1GB. The firmware stores the acquiring data in form of binary files. The DDL was designated to be compact and light and to consume low energy as possible. The DDL is to interface with PC through USB(Universal Serial Bus). The performance of the DDL has been validated through tests with respect to a 3-axis seismometer.

• 한국군사과학기술학회지
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• 제11권5호
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• pp.23-33
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• 2008

In this paper, we verify the performance of LDPC coded OFDM/DS system by Monte-Carlo simulation of BER on Eb/No. The simulation results show that LDPC coded OFDM/DS has a strong anti-jamming characteristic over pulse-noise jammer and partial-band noise jammer. The performance of LDPC coded OFDM/DS system is evaluated on both faded waveforms and non-faded waveforms. For non-faded waveforms, high coding gain is attained due to LDPC, even when waveforms have short PN sequence and JSR is only 5dB. Especially, the increase in the repeated number of LDPC decoding enhances coding gain. However, faded waveforms cannot achieve sufficient average effect when PN sequence is short. High coding gain of faded waveforms can be achieved by extending length of PN sequence. In addition, we compare LDPC coded OFDM/DS system with Convolutional coded OFDM/DS system. The simulation results illustrate that when LDPC coded OFDM/DS system with short PN sequence has sufficient average effects, the system shows lower BER than Convolutional coded OFDM/DS system with long PN sequence.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.230-233
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• 2003

In this paper, it is shown that, in DS/CDMA mobile systems, halving or doubling the spreading factor (HSF or DSE) when retransmission is requested possibly improves the throughput. Given transmit power, DSF essentially decreases probability of packet error (PPE) by increasing the signal energy per information bit. It, however, doubles the time duration needed for transmitting the original packet. On the other hand, HSF increases PPE. It, however halves the time duration required to carry the original packet. Thus, the efficiency of HSF or DSF as a retransmission strategy depends on the amount of increased or reduced PPE after HSF or DSF is selected. With achieving given residual error probability (REP) in CDMA systems, the effective throughput is evaluated in this paper to find conditions with which HSF or DSF achieves better performance than using the original one. Analytic results show that HSF or DSF performs better when relatively small or big changes in their PPE's are present, respectively.

• 대한정형도수물리치료학회지
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• 제19권1호
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• pp.79-83
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• 2013

Background: Spasmodic torticollis is a disorder that is described by sustained muscle contractions causing repetitive and twisting movements, and abnormal postures in a single body region. The purpose of this case is to describe the manual therapy for a patient with spasmodic torticollis. Methods: The patient was a 64 years old man with an 3 month history of left side laterocollis spasmodic torticollis. No known genetic history or trauma. Prior to intervention, his score on the Western Spasmodic Torticollis Rating Scale (TWSTRS) severity score was 24, disability score was 20, pain score was 11. There is a noticeable distinction between left and right side cervical range of motion. The intervention consisted of manual therapy (MET, PNF) 3 times per week for the treatment during 4 weeks. Results: After intervention for 4weeks, his TWSTRS score and range of motion was improved quite a bit before therapeutic exercise. But symptoms are not improving sufficiently fast. Conclusions: Manual therapy is that MET and PNF is effective in improving for patient had spasmodic torticollis with laterocollis of neck.

• Journal of Communications and Networks
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• 제15권4호
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• pp.352-361
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• 2013

Combining multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) with a massive number of transmit antennas (massive MIMO-OFDM) is an attractive way of increasing the spectrum efficiency or reducing the transmission energy per bit. The effectiveness of Massive MIMO-OFDM is strongly affected by the channel state information (CSI) estimation method used. The overheads of training frame transmission and CSI feedback decrease multiple access channel (MAC) efficiency and increase the CSI estimation cost at a user station (STA). This paper proposes a CSI estimation scheme that reduces the training frame length by using a novel pilot design and a novel unitary matrix feedback method. The proposed pilot design and unitary matrix feedback enable the access point (AP) to estimate the CSI of the signal space of all transmit antennas using a small number of training frames. Simulations in an IEEE 802.11n channel verify the attractive transmission performance of the proposed methods.

• ETRI Journal
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• 제26권5호
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• pp.375-383
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• 2004

This paper proposes a common interleaving method associated with independent channel-encoding among transmitter antenna branches in orthogonal frequency and code division multiplexing based on multiple-input multiple-output (MIMO) multiplexing to achieve an extremely high throughput such as 1 Gbps using a 100 MHz bandwidth. This paper also investigates the average packet error rate performance as a function of the average received signal energy per bit-to-background noise power spectrum density ratio $(E_b/N_0)$. We found that the loss in the required average received $E_b/N_0$ of the proposed method is only within approximately 0.3 dB in up to a 12-path Rayleigh fading channel, using 16QAM and Turbo coding with a coding rate of 5/6. We also clarify that even for a large fading correlation among antenna branches, 1 Gbps is still possible by increasing the transmission power. Therefore, the proposed method reduces the processing rate to 1/4 in the turbo decoder with only a slight loss in the required average received $E_b/N_0$.

• ETRI Journal
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• 제33권4호
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• pp.528-536
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• 2011

In this paper, we analyze the location accuracy of real-time locating systems (RTLSs) in multipath environments in which the RTLSs comply with the ISO/IEC 24730-2 international standard. To analyze the location error of RTLS in multipath environments, we consider a direct path and indirect path, in which time and phase are delayed, and also white Gaussian noise is added. The location error depends strongly on both the noise level and phase difference under a low signal-to-noise ratio (SNR) regime, but only on the noise level under a high SNR regime. The phase difference effect can be minimized by matching it to the time delay difference at a ratio of 180 degrees per 1 chip time delay (Tc). At a relatively high SNR of 10 dB, a location error of less than 3 m is expected at any phase and time delay value of an indirect signal. At a low SNR regime, the location error range increases to 8.1 m at a 0.5 Tc, and to 7.3 m at a 1.5 Tc. However, if the correlation energy is accumulated for an 8-bit period, the location error can be reduced to 3.9 m and 2.5 m, respectively.

• ETRI Journal
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• 제38권1호
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• pp.90-99
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• 2016

In this work, we investigate differentially encoded blind transceiver design in low signal-to-noise ratio (SNR) regimes for orthogonal frequency-division multiplexing (OFDM) signaling. Owing to the fact that acquisition of channel state information is not viable for short coherence times or in low SNR regimes, we propose a time-spread frequency-encoded method under OFDM modulation. The repetition (spreading) of differentially encoded symbols allows us to achieve a target energy per bit to noise ratio and higher diversity. Based on the channel order, we optimize subcarrier assignment for spreading (along time) to achieve frequency diversity of an OFDM modulated signal. We present the performance of our proposed transceiver design and investigate the impact of Doppler frequency on the performance of the proposed differentially encoded transceiver design. To further improve reliability of the decoded data, we employ capacity-achieving low-density parity-check forward error correction encoding to the information bits.