• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.90-97
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• 2006

We report our research work on the millimeter-wave broadband amplifier integrating the shunt peaking technology with the cascode configuration. The millimeter-wave broadband cascode amplifier on MIMIC technology was designed and fabricated using $0.1{\mu}m\;{\Gamma}-gate$ GaAs PHEMT, CPW, and passive library. The fabricated PHEMT has shown a transconductance of 346.3 mS/mm, a current gain cut off frequency ($f_T$) of 113 GHz, and a maximum oscillation frequency ($f_{max}$) of 180 GHz. To prevent oscillation of designed cascode amplifier, a parallel resistor and capacitor were connected to drain of common-gate device. For expansion of the bandwidth and flatness of the gain, we inserted the short stub into bias circuits and the compensation transmission line between common-source device and common-gate device, and then their lengths were optimized. Also, the input and output stages were designed using the matching method to obtain the broadband characteristic. From the measurement, we could confirm to extend bandwidth and flat gain by integrating the shunt peaking technology with the cascode configuration. The cascode amplifier shows the broadband characteristic from 19 GHz to 53.5 GHz. Also, the average gain of this amplifier is about 6.5 dB over the bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.93-98
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• 2004

Serial ATA interface Is inexpensive comparatively and performance is superior. So it is suitable technology in demand that now require data transmission and throughput of high speed. This paper describes a design and implementation of Serial ATA Link layer about error detection and 8b/10b encoder/decoder for DC balance in frequency 150MHz. The 8b/10b Encoder is partitioned into a 5b/6b plus a 3b/4b coder. The logical model of the block is described by using Verilog HDL at register transistor level and the verified HDL is synthesized using standard cell libraries. And it is fabricated with $0.35{\mu}m$ Standard CMOS Cell library and the chip size is about $1500{\mu}m\;*\;1500{\mu}m$. The function of this chip has been verified and tested using testboard with FPGA equipment and IDEC ATS2 test equipment. It is used to frequency of 100MHz in verification processes and supply voltage 3.3V. The result of testing is well on the system clock 100MHz. The designed and verified each blocks may be used IP in the field of high speed serial data communication.

• Development and Reproduction
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• v.2 no.1
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• pp.89-99
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• 1998

This study was carried out to investigate the morphological changes of gonadotropes in pituitary gland and spermatogenic cells in testis, obtained from 150 of 3-year-old immature and mature male rainbow trout (Oncorhynchus mykiss) during the reproductive cycles from March to February in the following year. In the maturation cycle of the pituitary gonadotropes of cultured rainbow trout, three periods can be distinguished i.e. a period of resting(March-August), a period of full spermatogenesis (September-November), and a period of breeding (December-February). The ultrastructures of the gonadotropes largely parallel the cyclical changes in the tests. The seminiferous tubules contain all spermatogenetic stages and sperm cells in a period of early maturation. At first, the size of the nucleus and cytoplasm decrease gradually at every stages from spermatogonia to spermatids. In the secondary spermatocytes, the small mitochondria are located over the outer cytoplam. In spermatids, the cytoplasmic masses move toward the posterior part of the nucleus. In spermatids, the two large mitochondria are located over the cytoplasm. In spermatids, the cytoplasmic masses move towark the posterior part of the nucleus. In spermatids, the two large mitochondria are located over the cytoplasm and begin to elongate. In spermatozoa, the surface of the nucleus devreases in volume. Examination by TEM shows that the nuclear envelope and plasma membrane are slightlywrinkled and closely adhered to the nucleus of spermatozoa. Two oval mitochondria are quite separated and the flagellum is inserted into the base of the spermatozoa head.The axoneme in this fish has the typical pattern such as nine peripheral doublets and a central doublet(9+2). there are remarkable individual differences in the size and morphology of spermatozoa head as observed by transmission and scanning electron microscopy.

• Applied Microscopy
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• v.35 no.4
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• pp.24-31
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• 2005

The preservative condition and ultrastructure on the mummified hair collected from newly found female mummy in Paju, were investigated by using scanning and transmission electron microscopes. The female mummy was found in september, 2002 during the traditional reburial process for the buried ones. The hair of 16th century mummy showed very intact appearances during observation with electron microscope. And the structures of the cortex, medulla and cuticle were well preserved. The cuticle layer was easily discernable, which are composed of six to seven cuticular cells. Each cuticular cells surrounded and thus seperated from its neighbors by intercellular membrane complex. In the cortex, many macrofibrils and some melanin granules between them were observed. We observed well preserved rod form macrofibrils running parallel along the direction of hair shaft. Especially, melanin granules were aggregated in the cortex which was adjacent to the cuticlu layer. As to the cause for the well-preservation of 440 year old hair sample, the presence of surface coat on the hair, which are composed of various materials. As calcium was included in the surface coat in Electron Dispersive X-ray Spectroscopy (EDS), the hardening process of the surface coat by calcium might inhibit the water or microorganism infiltration into the hair.

• Journal of the Korean Vacuum Society
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• v.19 no.5
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• pp.377-384
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• 2010

Many routes have been developed for the synthesis of signle-walled carbon nanotubes (SWCNTs). We spun fibers of SWCNTs directly from vertical furnace using a liquid source of carbon and an iron-contained molecule. The solution was prepared by ethanol as a carbon source, in which ferrocene as a catalyst, thiophene were dissolved. It was then injected from the top of the furnace into hot zone with hydrogen as a carrier gas. We successfully synthesized high-quality SWCNTs by adjusting the various experimental conditions, such as concentration of ferrocene, solution injection rate, concentration of thiophene, and hydrogen flow rate. Measurement of Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were carried out to find the optimized conditions. The synthesized SWCNTs (1.16~1.64 nm) appeared a bundle structure and well-aligned parallel to the direction of furnace. These results also provide an simple way for high-quality SWCNTs mass production and fabricating direct spining SWCNTs fiber. It will allow one-step production of SWCNTs fiber with potentially excellent properties and wide-range applications.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.205-216
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• 2010

In this paper, a method of MPEG-2 Transport Stream (TS) multiplexing for Ultra HDTV (UHDTV) and its design and implementation as a SW tool is described. In practice, UHD video may be divided into several HD videos and each video is encoded in parallel. Therefore, it is necessary to synchronize and multiplex multiple bitstreams encoding each HD video for transmitting and storing UHD video. In this paper, it is assumed that 4 HD videos partitioning a UHD spatially are encoded as H.264/AVC and two 5.0 channel audios are encoded by AC-3. Therefore, 4 H.264/AVC elementary streams (ESs) and 2 AC-3 ESs is mainly considered in the TS multiplexing of UHD. For the carriage of H.264/AVC and AC-3 over MPEG-2 TS, PES packetization and TS multiplexing are designed and implemented based on the extended specification of the MPEG-2 Systems and ATSC (Digital audio compressed standard), respectively. The implemented UHD TS multiplexing tool emulates real time HW operation in the time unit corresponding to the duration of one TS packet transmission in a given TS rate. In particular, in order to satisfy the timing model, the buffers defined in the TS System Target Decoder (T-STD) are monitored and their statuses are considered in the scheduling of TS multiplexing. For UHD multiplexing, two kinds of multiplexing structures, which are UHD re-multiplexing and UHD program multiplexing, are implemented and their strength and weakness are investigated. The developed UHD TS multiplexing tool is tested and verified in terms of the syntax and semantics conformance and functionalities by using a commercial analyzer and real-time presentation tools.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.401-412
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• 2003

In this paper, a broadband phase shifter structure using a new switched network was proposed. A new reference network is composed of coupled lines and 45$^{\circ}$open and short stubs, which are shunted at the edge points of a main line, respectively, A delay network is composed of only a standard transmission line. It is possible to design a broadband 180$^{\circ}$phase shifter that phase dispersive characteristics by an impedance ratio R of coupled lines and greater phase dispersive characteristics by characteristic impedances Zm, Zs of a main line and stubs are used together. By considering a structure symmetry, the even and odd mode analysis was performed to obtain theoretical S-parameters of the proposed phase shifter. Also, through computer simulation on the basis of derived equations, design graphs were presented to optimally design a 180$^{\circ}$broadband phase shifter. Design graphs provide the values of characteristic impedances Zm, Zs, and I/O match and phase bandwidths. To verify electrical performances of the broadband phase shifter proposed in this paper, low different 180$^{\circ}$phase shifters, operated at the center frequency 3 GHz were designed and fabricated using design graphs, and were experimented. One of them was designed as a standard Schiffman structure to compare with electrical performances. Measured results of each phase shifter to satisfy simultaneously design conditions of I/O match （VSWR=1.15:1) and maximum phase deviation $({\varepsilon}_{{\Delta}{\phi}}＝{\pm}2^{\circ})$ were well in agreement with corresponding simulation results over impedance match and phase error bandwidths, and showed broadband characteristics.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.595-599
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• 2009

Sarcocystis grueneri-like sarcocysts were found from the cardiac muscles of a rearing red deer (Cervus elaphus) carcass in Korea. In the light microscopical examination of sarcocysts, they were oval to spherical cysts and 90-170$\times$110-380 ${\mu}m$ in size. However, there was no inflammation and myofiber degeneration. In the transmission electron microscope, these cysts were located within the sarcoplasm of the host cell and filled with merozoites. The sarcocysts were enclosed by a very thin wall (0.45-0.6 ${\mu}m$ thick) that consists of protrusions and ground substance. The primary cyst wall formed numerous strip-like protrusions which were 0.2-0.3 ${\mu}m$ wide and up to 4.2 ${\mu}m$ long. The protrusions were running in parallel with the surface of the cyst. A characteristic of the cyst wall was absent of fibrils inside the protrusions. Merozoites in the compartment measured about $15\times4\;{\mu}m$. The merozoite consisted of four regions: micronemes and rhoptries, amylopectin granule, nucleus, and amylopectin granules. The number of rhoptry was counted in 7-13.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.307-314
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• 2010

Although conventional seismic data processing is based on the assumption that the media are isotropic, the subsurface is often anisotropy in shale formation or carbonate with cracks and fractures. This paper presents the anisotropic parameter and seismic modeling in transversely isotropic media with a vertical symmetry axis using seismic physical modeling. The experiment was successfully carried out with VTI media, laminated bakelite material, using contact transducer of p and s-wave transmission. The variation of velocities with angle of incidence was clearly shown in anisotropic material. Comparing these velocities with the calculated phase velocities, the (P) and (S)-wave velocity observed in anisotropic material was a very good agreement with the calculated values. Anisotropic parameter ${\varepsilon}$, ${\delta}$, ${\gamma}$ was estimated by using Lame's constant calculated from the observed velocity. For the purpose of testing (S)-wave polarization, a birefringence experiment was carried out. The higher velocity was associated with the polarization parallel to the fracture, and the lower velocity was associated with the polarization perpendicular to the fracture.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.213-218
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• 2015

In parallel with evolving information communication technology, M2M(Machine-to-Machine) industry has implemented multi-functional and high-performance systems, and made great strides with IoT(Internet of Things) and IoE(Internet of Everything). Authentication, confidentiality, anonymity, non-repudiation, data reliability, connectionless and traceability are prerequisites for communication security. Yet, the wireless transmission section in M2M communication is exposed to intruders' attacks. Any security issues attributable to M2M wireless communication protocols may lead to serious concerns including system faults, information leakage and privacy challenges. Therefore, mutual authentication and security are key components of protocol design. Recently, secure communication protocols have been regarded as highly important and explored as such. The present paper draws on hash function, random numbers, secret keys and session keys to design a secure communication protocol. Also, this paper tests the proposed protocol with a formal verification tool, Casper/FDR, to demonstrate its security against a range of intruders' attacks. In brief, the proposed protocol meets the security requirements, addressing the challenges without any problems.