• Journal of Korea Foresty Energy
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• v.25 no.1
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• pp.9-17
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• 2006

Properties of wood charcoal made from the domestic wood species at $300-900^{\circ}C$ have investigated to understand the correlation between carbonization temperature and chemical and physical characteristics of wood charcoal. In terms of charcoal yield at particular carbonization temperatures, it was drastically decreased until the temperature reaches up to $600^{\circ}C$ and the decrease ratio of yield was reduced at higher temperatures. As the carbonization temperature increased, pH of the wood charcoal increased so that it became basic at last. The wood charcoal prepared at $600{\sim}700^{\circ}C$ showed the highest caloric value and those of wood charcoals made at higher temperature became plateau at a little lower level than the peak. The caloric value of Japanese larch charcoal was a bit higher than that of Red oak charcoal. The carbon content in the wood charcoal was increased as the carbonization temperature increased, whereas the hydrogen content was decreased. Specific surface area of the wood charcoal became larger with increase in temperature up to $600^{\circ}C$ but it was decreased or reduced in the increasing ratio after, and then it rose again at higher temperature than $800^{\circ}C$. Absorption capacity of the wood charcoal against iodine and gaseous acetic acid became greater as the carbonization temperature increased. Japanese larch charcoal presented higher absorption capacity than Red oak charcoal. As the above results, it is revealed that carbonization temperature affects the chemical and physical properties of wood charcoal. Therefore, to use wood charcoal with maximum effect it should be prepared at optimum temperature for proper use.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.1-7
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• 2018

The IoT environment provides an infinite variety of services using many different devices and networks. The development of the IoT environment is directly proportional to the level of security that can be provided. In some ways, lightweight cryptography is suitable for IoT environments, because it provides security, higher throughput, low power consumption and compactness. However, it has the limitation that it must form a new cryptosystem and be used within a limited resource range. Therefore, it is not the best solution for the IoT environment that requires diversification. Therefore, in order to overcome these disadvantages, this paper proposes a method suitable for the IoT environment, while using the existing block cipher algorithm, viz. the lightweight cipher algorithm, and keeping the existing system (viz. the sensing part and the server) almost unchanged. The proposed BCL architecture can perform encryption for various sensor devices in existing wire/wireless USNs (using) lightweight encryption. The proposed BCL architecture includes a pre/post-processing part in the existing block cipher algorithm, which allows various scattered devices to operate in a daisy chain network environment. This characteristic is optimal for the information security of distributed sensor systems and does not affect the neighboring network environment, even if hacking and cracking occur. Therefore, the BCL architecture proposed in the IoT environment can provide an optimal solution for the diversified IoT environment, because the existing block cryptographic algorithm, viz. the lightweight cryptographic algorithm, can be used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.699-707
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• 2016

This paper proposes a low-complexity central processing unit (CPU) that is suitable for deeply embedded systems, including Internet of things (IoT) applications. The core features a 16-bit instruction set architecture (ISA) that leads to high code density, as well as a multicycle architecture with a counter-based control unit and adder sharing that lead to a small hardware area. A co-processor, instruction cache, AMBA bus, internal SRAM, external memory, on-chip debugger (OCD), and peripheral I/Os are placed around the core to make a system-on-a-chip (SoC) platform. This platform is based on a modified Harvard architecture to facilitate memory access by reducing the number of access clock cycles. The SoC platform and CPU were simulated and verified at the C and the assembly levels, and FPGA prototyping with integrated logic analysis was carried out. The CPU was synthesized at the ASIC front-end gate netlist level using a $0.18{\mu}m$ digital CMOS technology with 1.8V supply, resulting in a gate count of merely 7700 at a 50MHz clock speed. The SoC platform was embedded in an FPGA on a miniature board and applied to deeply embedded IoT applications.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.5
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• pp.469-484
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• 2016

HR-ToF-AMS was applied for a seasonal and size-distributional measurements for inorganic ($SO{_4}^{2-}$, $NO_3{^-}$, $NH_4{^+}$, $Cl^-$) and organic components in Baegryung Island Super Site. The average concentration of $PM_{1.0}$ remarks $12.9{\mu}g/m^3$ while $14.5{\mu}g/m^3$ in Spring time, $14.2{\mu}g/m^3$ in Winter, $13.1{\mu}g/m^3$ in Summer and $9.86{\mu}g/m^3$ in Autumn. The mass of measured $PM_{1.0}$ shows 54.6% of $PM_{2.5}$ which is similar to those of Beijing and Lanzhou, China. The highest portion of Chemical composition is $SO{_4}^{2-}$ marking 41.0%, 31.8% by organics, 13.5% by $NH_4{^+}$, 12.8% by $NO_3{^-}$ and 1% by $Cl^-$. In every seasons, except winter, $SO{_4}^{2-}$ remarks the highest level, organic components take place the highest in winter time. The size-distribution of $PM_{1.0}$ components scattered at accumulation mode of 200 nm~800 nm which means the influence of primary emission is low. In case of air stream from the industrialized area of Sandung, Shanghai, China, the concentrations of such components were distributed a bit higher.

• 대한공업교육학회지
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• v.36 no.2
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• pp.181-199
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• 2011

The purpose of this study is to determine the level of key competencies and teacher efficacy of pre-service industrial teachers as related to their personal backgrounds, and to analyze the correlation between personal variables, key competencies and teaching efficacy. This will be provided as basic resources for pre-service teacher training program to improve the understanding of key competencies and teaching efficacy of pre-service industrial teachers. The results of this study are as follows. First, the teacher efficacy of pre-service industrial teachers was found to be above average (M=3.0), and teaching efficacy (M=3.41) was found to be a bit higher than personal teacher efficacy (M=3.28). Upon analyzing the significant differences of teacher efficacy resulting from background variables, it was found that gender and major had no difference while the effect of school year on teaching efficacy of teacher efficacy showed statistically significant differences. Second, the lower regions of key competencies of pre-service industrial teachers all were above the average 3.0. Gender and school year were exhibited no significant difference, and only the global competence of key competencies showed significant difference. Third, it was found that the gender and major of pre-service industrial teachers had no correlation with teacher efficacy and key competencies. On the other hand, school year variable showed significant positive correlation with teacher efficacy (r=.274) and key competencies (r=.168). Lastly, it was found that key competencies and teacher efficacy had positive correlation of r=.475.

• Journal of Korean Physical Therapy Science
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• v.6 no.1
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• pp.897-903
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• 1999

Many out patients of the rehabilitation center complaint a pain caused by suffering of MPS, and it brings many different kind of social and ecinomical problems such as medical expenses and the reduction in work efficiency. Therefore, we conducted a research to present a fast and effective treatment to the MPS patients. this research was conducted from November, 1996 to January 1998 with eighteen outpatients who agreed to be the subjects to our reserach. We applied the electric acupuncture on 28 different trigger point on the patients with mostly muscular-skeletal pain and some tender and radiating pain. After the treatment, VRS, VAS, PRI were used to measure the degree of the pain on the patients third and seventh visits, and following results were found. 1. To apply EAP treatment, we acupunctured 6em-Iong needles on Tps region, then the electrodes of pulse generater pg-306 E.S.T were connected on the top of the needles. the electric acupuncture therapy was conducted for 20 minutes with the intensity of 4hz - 60hz(auto wave). The treated electric intensity was the level at which the patients did not feel discomfort. 2. Thirteen out of the 18 participated patients were in their 30s and 40s(72.2%), showing highest frequency. There were more female than male with the ratio of 1 to 1:2. 3. six out of the participated patients (33.3%) had the pain for less then a week, and the average duration of the pain of the participated patients wear 0.8 years. 4. The pain occured mostly in the upper trapezius by 6 part (21.4%), then in the gluteus medius region by 4 part (14.3%). Many of the patients with the pain in the upper back area accompanied varios kind of the referred pains such as radiculopathy, HIVD and Frozen shoulder. 5. MPS occured more frequently on the right side than left side then left side and it seemed to be due to the frequent use of the right hand. 6. There was almost no difference in the measurement of the intensity of the pain right before and after the EAP treatment. Howerver, there was significant decrease in the numerical values of the VAS, and a little bit of decrease in the numerical values of the PRI after the EAP treatment. 7. Based on the results of this present research, it can be concluded that EAP can be used for the treating the myofascial pain syndrome with promptness and safety in most cases.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.3 s.333
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• pp.25-34
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• 2005

In this paper, we analyzed and measured the electrical crosstalk characteristics of a triplex transceiver module for ethernet Passive optical networks(EPONS). And we improved the electrical crosstalk levels using Dummy ground lines with signal lines. The triplex transceiver module consists of a laser diode as a transmitter, a digital photodetector as a digital data receiver, and a analog photodetector as a community antenna television signal receiver. And there are integrated on silicon substrate. The digital receiver and analog receiver sensitivity have to meet -24 dBm at $BER=10^{-l2}$ and -7.7 dBm at 44 dB SNR. And the electrical crosstalk levels have to maintain less than -86 dB from DC to 3 GHz. From analysis and measurement results, the proposed silicon substrate structure that contains the Dummy ground line with $100\;{\mu}m$ space from signal lines and separates 4 mm among devices respectively, is satisfied the electrical crosstalk level compared to simple structure. This proposed structure can be easily implemented with design convenience and greatly reduced the silicon substrate size about $50\%$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.6-12
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• 2010

A sigma-delta modulator based class-D audio amplifier is presented. Parallel digital input is serialized to two-bit output by a fourth-order digital sigma-delta noise shaper. The output of the digital sigma-delta noise shaper is applied to a fourth-order analog sigma-delta modulator whose three-level output drives power switches. The pulse density modulated (PDM) output of the power switches is low-pass filtered by an LC-filter. The PDM output of the power switches is fed back to the input of the analog sigma-delta modulator. The first integrator of the analog sigma-delta modulator is a hybrid of continuous-time (CT) and switched-capacitor (SC) integrator. While the sampled input is applied to SC path, the continuous-time feedback signal is applied to CT path to suppress the noise of the PDM output. The class-D audio amplifier is fabricated in a standard $0.13-{\mu}m$ CMOS process and operates for the signal bandwidth from 100-Hz to 20-kHz. With 4-${\Omega}$ load, the maximum output power is 18.3-mW. The total harmonic distortion plus noise and dynamic range are 0.035-% and 80-dB, respectively. The modulator consumes 457-uW from 1.2-V power supply.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.1-11
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• 2012

The multi-code spread spectrum communication system, which spreads data bit stream by multiplexing orthogonal codes, can transmit data in high rate. However it needs the high-cost good linear amplifier because of the multi-level output signal. In order to overcome this drawback several systems making the amplitude of output signal constant with Walsh codes have been proposed. Recently constant amplitude pre-coded multi-code spread spectrum systems using extended m-sequence have been proposed. In this paper we consider an extended m-sequence based constant amplitude multi-code spread spectrum system with code set partitioning. By grouping the orthogonal codes into 4 subsets, not only is the computational complexity of the transceiver reduced but BER performance also improves. It has been shown that parity checking on four detected codes at the receiver can correct code detection error and result in BER performance enhancement. In this paper we propose a improved parity check receiver. We carried out computer simulation to verify feasibility of the proposed algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.89-101
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• 2014

Recently, as domestic air traffic dramatically increases, the need of ATC(air traffic control) systems has grown for safe and efficient ATM(air traffic management). Especially, for smooth ATC, it is far more important that performance of display system which should show all air traffic situation in FIR(Flight Information Region) without additional latency is guaranteed. In this paper, we design a ASTERIX(All purpose STructured Eurocontrol suRveillance Information eXchange) parsing module to promote stable ATC by minimizing system loads, which is connected with reducing overheads arisen when we parse ASTERIX message. Our ASTERIX parsing module based on pattern matching creates patterns by analyzing received ASTERIX data, and handles following received ASTERIX data using pre-defined procedure through patterns. This module minimizes display errors by rapidly extracting only necessary information for display different from existing parsing module containing unnecessary parsing procedure. Therefore, this designed module is to enable controllers to operate stable ATC. The comparison with existing general bit level ASTERIX parsing module shows that ASTERIX parsing module based on pattern matching has shorter processing delay, higher throughput, and lower CPU usage.