• Bulletin of the Korean Mathematical Society
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• v.43 no.4
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• pp.723-735
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• 2006

In [2] it was shown that a 1-generator quasi-cyclic code C of length n = ml of index l over $\mathbb{Z}_4$ is free if C is generated by a polynomial which divides $X^m-1$. In this paper, we prove that a necessary and sufficient condition for a cyclic code over $\mathbb{Z}_pk$ of length m to be free is that it is generated by a polynomial which divides $X^m-1$. We also show that this can be extended to finite local rings with a principal maximal ideal.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.12
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• pp.37-42
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• 1997

A new temperature and supply-insensitive CMOS current reference circuit was designed and tested. Te temperature insensuitivity was achieved by eliminating the mobility dependence term through the multiplication of two current components, one which is proportional to mobility and the other which is inversely proportional to mobility, by using a newly designed CMOS square root circuit. The CMOS sqare root circuit was derived from its bipolar counterpart by operating the MOS transistors in the subthreshold region. The supply insensitivity was achieved by using an internal voltage generator. Te test chip was designed ans sent out for fabrication by using a 2.mu.m double-poly double-metal n-well CMOS technology. When an external voltage source was used for the square root circuit, the maximum variation and the average temperature sensitivity were measured to be 3% and 21.4ppm/.deg.C, respectively, for the temperature range of -15~130.deg.C. The maximum current variation with supply voltage was measured to be 3% within the commerical supply voltage range of 4.5~5.5V at 30.deg. C.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.2
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• pp.130-137
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• 1988

The technique of dual-input describing function's synthesis is introduced and the construction of a nonlinear compensator, based on this technique, is proposed. A nonlinear compensator, describing a complex DIDF depending upon amplitude of the second sinusoidal input signal only, is also proposed, where the second sinusoidal input signal is supplied to the nonlinear compensator by external generator. This compensator, connected in a closed loop of the PI speed control of DC motor, can improve the speed response in view instability limit cycle, low speed response and disturbance of the dynamic shift of the Nyquist's critical point -1 + j O. It is verified theoretically that the improvement of speed response of DC motor using the proposed compensator is achieved by means of the dynamic shift of the Nyquist's critical point on the complex plane, and the speed characterstics of DC motor is to be tested through experiment for its performance.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.10
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• pp.410-422
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• 1984

This paper presents a new practical method for optimal active and reactive power control for the economic operation in electrical power system, and the programs are developed for digital computer solution. The major features and techniques of this paper are as follows: 1) The method is presented for finding the equivalent active power balance equation applying the sparse Jacobian matrix of power flow equation instead of using B constant as active power balance equation considering transmission loss, and thus for determining directly optimal active power allocation berween generator unitw satisfying the equality and inequality constraints. 2) The method is proposed for solving directly the optimum economim dispatch problem without using gradient method and penalty function for both active and reactive power control. As a result, the computing time are reduced and convergence characteristic is remarkably improved. 3) Unlike most of conventional methods which adopt the transmission loss as a objective function for reactive power control, the total fuel cost of themal power plant is adopted as objective function for both active and reactive power control. consequently, more reasonable and economic profit can be achieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1576-1581
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• 2000

We investigated into the minimum distance of a primitive binary cyclic code C with a generator polynomial g(x)=$m_1(x)m_{d}(x)$. It is known that the necessary and sufficient condition for C to have minimum distance five is the fact that \ulcorner is an APN power function. In this paper we derived the new proof of minimum distance for the primitive binary cyclic codes with minimum distance five.

• The Korean Journal of Pain
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• v.33 no.2
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• pp.99-107
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• 2020

Chronic severe pain results in a detrimental effect on the patient's quality of life. Such patients have to take a large number of medications, including opioids, often without satisfactory effect, sometimes leading to medication abuse and the pain worsening. Spinal cord stimulation (SCS) is one of the most effective technologies that, unlike other interventional pain treatment methods, achieves long-term results in patients suffering from chronic neuropathic pain. The first described mode of SCS was a conventional tonic stimulation, but now the novel modalities (high-frequency and burst), techniques (dorsal root ganglia stimulations), and technical development (wireless and implantable pulse generator-free systems) of SCS are becoming more popular. The improvement of SCS systems, their miniaturization, and the appearance of new mechanisms for anchoring electrodes results in a significant reduction in the rate of complications and revision surgeries, and the appearance of new waves of stimulation allows not only to avoid the phenomenon of addiction, but also to improve the long-term results of chronic SCS. The purpose of this review is to describe the current condition of SCS and up-to-date technical advances.

• The Korean Journal of Nuclear Medicine
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• v.36 no.3
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• pp.195-202
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• 2002

Purpose: For clinical application of beta-emitter labeled antibody, high specific activity is imporiant. Carrier-free $^{188}Re$ from $^{188}W/^{188}Re$ generator is an ideal radionuclide for this purpose. However, low stability of $^{188}Re$ labeled antibody, especially in high specific activity, due to radiolytic decomposition by high energy (2.1 MeV) beta ray was problem. We studied the stability of $^{188}Re$ labeled antibody, and stabilizing effect of several stabilizers. Materials and Methods: Pre-reduced monoclonal antibody (CEA79.4) was labeled with $^{188}Re$ by incubating with generator-eluted $^{188}Re-perrhenate$ in the presence of stannous tartrate for 2 hr at room temperature. Radiochemical purity of each preparation was determined by chromatography. Human serum albumin was added to the labeled antibodies (2%). Stability of $^{188}Re-CEA79.4$ was investigated in the presence of ascorbic acid, ethanol, of Tween 80 as stabilizing agents. Results: Labeling efficiencies were $88{\pm}4%\;(n=12)$. Specific activities of $1.25{\sim}4.77MBq/{\mu}g$ were obtained. If stored after purging with $N_2$, all the preparations were stable for 10 hr. However, stability decreased in the presence of air. Perrhenate and $^{188}Re-tartrate$ was major impurity in declined preparation. colloid-formation was not a significant problem in all cases. Addition of ascorbic acid stabilized the labeled antibodies either under $N_2$ or under air by reducing the formation of perrhenate. Conclusion: High specific activity $^{188}Re$ labeled antibody is unstable, especially, in the presence of oxygen. Addition of ascorbic acid increased the stability.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.673-679
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• 1997

It has been generally accepted that glutamate mediates the ischemic brain damage, excitotoxicity, and induces release of neurotransmitters, including norepinephrine(NE), in ischemic milieu. In the present study, the role of nitric oxide(NO) in the ischemia-induced $[^3H]norepinephrine([^3H]NE)$ release from cortex slices of the rat was examined. Ischemia, deprivation of oxygen and glucose from $Mg^{2+}-free$ artificial cerebrospinal fluid, induced significant release of $[^3H]NE$ from cortex slices. This ischemia-induced $[^3H]NE$ release was significantly attenuated by glutamatergic neurotransmission modifiers. $N^G-nitro-L-arginine$ methyl ester(L-NAME), $N^G-monomethyl-L-arginine$ (L-NMMA) or 7-nitroindazole, nitric oxide synthase inhibitors attenuated the ischemia-evoked $[^3H]NE$ release. Hemoglobin, a NO chelator, and 5, 5- dimethyl-L-pyrroline-N-oxide(DMPO), an electron spin trap, inhibited $[^3H]NE$ release dose-dependently. Ischemia-evoked $[^3H]NE$ release was inhibited by methylene blue, a soluble guanylate cyclase inhibitor, and potentiated by 8-bromo-cGMP, a cell permeable cGMP analog, zaprinast, a cGMP phosphodiesterase inhibitor, and S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide generator. These results suggest that the ischemia-evoked $[^3H]NE$ release is mediated by NMDA receptors, and activation of NO system is involved.

• Journal of IKEEE
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• v.20 no.2
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• pp.192-195
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• 2016

In this paper, we present a nanopower CMOS bandgap voltage reference working in sub-threshold region without resisters and bipolar junction transistors (BJT). Complimentary to absolute temperature (CTAT) voltage generator was realized by using two n-MOSFET pair with body bias circuit to make a sufficient amount of CTAT voltage. Proportional to absolute temperature (PTAT) voltage was generated from differential amplifier by using different aspect ratio of input MOSFET pair. The proposed circuits eliminate the use of resisters and BJTs for the operation in a sub-1V low supply voltage and for small die area. The circuits are implemented in 0.18um standard CMOS process. The simulation results show that the proposed sub-BGR generates a reference voltage of 290mV, obtaining temperature coefficient of 92 ppm/$^{\circ}C$ in -20 to $120^{\circ}C$ temperature range. The circuits consume 15.7nW at 0.63V supply.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.254-254
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• 2011

The memories with nano-particles are very attractive because they are promising candidates for low operating voltage, long retention time and fast program/erase speed. In recent, various nano-floating gate memories with metal-oxide nanocrystals embedded in organic and inorganic layers have been reported. Because of the carrier generation in semiconductor, induced photon pulse enhanced the program/erase speed of memory device. We studied photo-induced electrical properties of these metal-oxide nanocrystal memory devices. At first, 2~10-nm-thick Sn and In metals were deposited by using thermal evaporation onto Si wafer including a channel with $n^+$ poly-Si source/drain in which the length and width are 10 ${\mu}m$ each. Then, a poly-amic-acid (PAA) was spin coated on the deposited Sn film. The PAA precursor used in this study was prepared by dissolving biphenyl-tetracarboxylic dianhydride-phenylene diamine (BPDA-PDA) commercial polyamic acid in N-methyl-2-pyrrolidon (NMP). Then the samples were cured at 400$^{\circ}C$ for 1 hour in N atmosphere after drying at 135$^{\circ}C$ for 30 min through rapid thermal annealing. The deposition of aluminum layer with thickness of 200 nm was followed by using a thermal evaporator, and then the gate electrode was defined by photolithography and etching. The electrical properties were measured at room temperature using an HP4156a precision semiconductor parameter analyzer and an Agilent 81101A pulse generator. Also, the optical pulse for the study on photo-induced electrical properties was applied by Xeon lamp light source and a monochromator system.