• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권5호
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• pp.2680-2700
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• 2017

Finite field arithmetic over GF($2^m$) is used in a variety of applications such as cryptography, coding theory, computer algebra. It is mainly used in various cryptographic algorithms such as the Elliptic Curve Cryptography (ECC), Advanced Encryption Standard (AES), Twofish etc. The multiplication in a finite field is considered as highly complex and resource consuming operation in such applications. Many algorithms and architectures are proposed in the literature to obtain efficient multiplication operation in both hardware and software. In this paper, a modified serial multiplication algorithm with interleaved modular reduction is proposed, which allows for an efficient realization of a sequential polynomial basis multiplier. The proposed sequential multiplier supports multiplication of any two arbitrary finite field elements over GF($2^m$) for generic irreducible polynomials, therefore made versatile. Estimation of area and time complexities of the proposed sequential multiplier is performed and comparison with existing sequential multipliers is presented. The proposed sequential multiplier achieves 50% reduction in area-delay product over the best of existing sequential multipliers for m = 163, indicating an efficient design in terms of both area and delay. The Application Specific Integrated Circuit (ASIC) and the Field Programmable Gate Array (FPGA) implementation results indicate a significantly less power-delay and area-delay products of the proposed sequential multiplier over existing multipliers.

• 대한건축학회논문집:구조계
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• 제36권5호
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• pp.187-194
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• 2020

This study presents the energy-saving sequential control algorithm to handle indoor CO₂ and PM2.5 for the improvement of the air quality of school classrooms. To solve indoor air quality (IAQ) problems, air cleaning and ventilation systems are mainly used for school classrooms. Although air cleaning is able to collect PM2.5, it is difficult to remove harmful gas substances. The ventilation system is suitable to tackle CO and CO₂, the volume ventilation, however, is relatively small. In this paper, to remove CO₂ and PM2.5, the pollutant balance equation for improving indoor air quality is reviewed. The sequential control algorithm of the ventilation and air cleaning system with four levels of criteria is introduced for the effective removal of pollutants. The proposed sequential control algorithm confirms that indoor CO₂ and PM2.5 can be properly controlled below the standard value. In addition, the sequential operation of air cleaning and ventilation systems has shown significant improvement in IAQ compared to the independent ventilation system operation. Particularly, such systems are efficient when outdoor PM2.5 is high.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.153-158
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• 2003

Catalytic Combustion used to be applied to specific conditions because of the characteristics different from flame combustion. However, many researches are focused on widening the applicant range of catalytic combustion with the competences of catalytic combustion. The development of many catalytic combustion appliances is one of the trials to overcome the restrictions of reaction and maximize the merits. In this research, past developments of appliances are depicted and new conceptual system will be introduced - sequential system. Sequential catalytic combustion system is composed of units - existing catalytic heat exchangers. This system is performed with parallel in composition and serially in operation. First, the burden of the preheating can be dramatically reduced. Second, stable operation control is expected. Lastly, Capacity expansion is flexible.

• 대한전자공학회논문지
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• 제24권5호
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• pp.896-904
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• 1987

In this paper, a design method for sequential circuit which is easy to have Built-in Self Test is kproposed using the functional advantages of multifunctional BILBO and LSSD. To achieve the hardware reduction, it is designed that a multifunctional BILBO has double operational functions of NLFSR and LFSR, when neccessary, and that test signal could be used as an input-output signal in the same line. By applying the proposed multifunctional BILBO to the sequential PLA, the test patterns and the additional circuit could be reduced in test operation and the propagation delay is vanished in normal operation, as we expected. Above them, the partitioned method for large scale sequential circuit is also suggested and it is observed that test patterns and additional circuit in them reduced by this method.

• 조명전기설비학회논문지
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• 제26권12호
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• pp.50-55
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• 2012

This paper presents an application of optimization method for efficient operation in micro grid. For operational efficiency, the objective function in a diesel generator consists of the fuel cost function similar to the cost functions used for the conventional fossil-fuel generating plants. The wind turbine generator is modeled by the characteristics of variable output. The cost function of fuel cell plant considers the efficiency of fuel cell. Particle swarm optimization(PSO) and sequential quadratic programming(SQP) are used for solving the problem of microgrid system operation. Also, from the results this paper presents the way to attend power markets which can buy and sell power from upper lever grids by connecting a various generation resources to micro grid.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권10호
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• pp.479-485
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• 2001

In this paper, we introduce a charge pump phase-locked loop (PLL) architecture which employs a precharge phase frequency detector (PFD) and a sequential PFD to achieve a high frequency operation and a fast acquisition. Operation frequency is increased by using the precharge PFD when the phase difference is within $-{\pi}{\sim}{\pi}$ and acquisition time is shortened by using the sequential PFD and the increased charge pump current when the phase difference is larger than ${\pm}{\pi}$. So error detection range of the proposed PLL structure is not limited to $-{\pi}{\sim}{\pi}$ and a high frequency operation and a higher speed lock-up time can be achieved. The proposed PLL was designed using 1.5 ${\mu}m$ CMOS technology with 5V supply voltage to verify the lock in process. The proposed PLL shows successful acquisition for 200 MHz input frequency. On the other hand, the conventional PLL with the sequential PFD cannot operate at up to 160MHz. Moreover, the lock-up time is drastically reduced from 7.0 ${\mu}s\;to\;2.0\;{\mu}s$ only if the loop bandwidth to input frequency ratio is regulated by the divide-by-4 counter during the acquisition process. By virtue of this dual PFDs, the proposed PLL structure can improve the trade-off between acquisition behavior and locked behavior.

• 항공우주시스템공학회지
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• 제11권4호
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• pp.22-29
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• 2017

비선형특성을 갖고 있는 실제 무인기용 소형터보제트엔진의 운전 중 발생하는 결함을 효과적으로 탐지하기 위한 방안에 대해 연구하였다. 이를 위해서 동적 열역학 사이클해석을 통한 비선형 동특성 모델을 도출하였다. 실제적인 운전상황의 연출을 위해 잡음특성의 평가에 부합하는 무향칼만필터를 적용하였고 필터성능이 가미된 제어기를 설계하였다. 엔진회전수 센서의 결함을 통한 엔진 결함발생을 모사하였고, 발생된 결함의 실시간적인 탐지 방안으로 연속확률비 평가기법을 도입하였다. 이를 운전 중 엔진결함탐지에 적용한 결과 분명한 결정양상을 보임으로써 매우 효과적이고 유용함을 확인하였다.

• Journal of Astronomy and Space Sciences
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• 제35권4호
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• pp.295-308
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• 2018

In this study, orbit determination (OD) simulation for the Korea Pathfinder Lunar Orbiter (KPLO) was accomplished for investigation of the observational arc-length effect using a sequential estimation algorithm. A lunar polar orbit located at 100 km altitude and $90^{\circ}$ inclination was mainly considered for the KPLO mission operation phase. For measurement simulation and OD for KPLO, the Analytical Graphics Inc. Systems Tool Kit 11 and Orbit Determination Tool Kit 6 software were utilized. Three deep-space ground stations, including two deep space network (DSN) antennas and the Korea Deep Space Antenna, were configured for the OD simulation. To investigate the arc-length effect on OD, 60-hr, 48-hr, 24-hr, and 12-hr tracking data were prepared. Position uncertainty by error covariance and orbit overlap precision were used for OD performance evaluation. Additionally, orbit prediction (OP) accuracy was also assessed by the position difference between the estimated and true orbits. Finally, we concluded that the 48-hr-based OD strategy is suitable for effective flight dynamics operation of KPLO. This work suggests a useful guideline for the OD strategy of KPLO mission planning and operation during the nominal lunar orbits phase.

• Archives of Plastic Surgery
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• 제46권5호
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• pp.449-454
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• 2019

Background Most patients with head and neck cancer successfully undergo oncologic resection followed by free or local flap reconstruction, depending on the tumor's size and location. Despite effective curative resection and reconstruction, head and neck cancer patients still face a high risk of recurrence and the possibility of a second primary cancer. Moreover, surgeons hesitate to perform sequential reconstruction following curative resection for several reasons. Few large-scale studies on this subject are available. Therefore, we retrospectively evaluated the outcome of sequential head and neck reconstruction to determine the possible risks. Methods In total, 467 patients underwent head and neck reconstruction following cancer resection at our center from 2008 to 2017. Of these cases, we retrospectively reviewed the demographic and clinical features of 58 who had sequential head and neck reconstruction following resection of recurrent cancer. Results Our study included 43 males (74.1%) and 15 females (25.9%). The mean age at the initial operation was $55.4{\pm}15.3years$, while the mean age at the most recent operation was $59.0{\pm}14.3years$. The interval between the first and second operations was $49.2{\pm}62.4months$. Twelve patients (20.7%) underwent surgery on the tongue, and 12 (20.7%) had procedures on the oropharynx. Thirty-four patients (58.6%) received a sequential free flap reconstruction, and 24 patients (41.4%) were treated using locoregional flaps. No cases of flap failure occurred. Conclusions Our findings suggest that patients who need additional operations with recurrent head and neck cancer could optimally benefit from sequential curative resections and reconstructions.

• 정보처리학회논문지B
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• 제11B권3호
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• pp.353-360
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• 2004

최근까지 MPEG으로 압축된 영상의 장면전환점 검출에 관한 연구가 많이 진행되어왔다. 그러나 대체로 디코딩 과정을 거친 후 픽셀단위의 비교를 통해 장면전환점을 검출하는 경우가 많았다. 이 경우 디코딩 과정에서의 많은 계산에 의해 실시간 적용에 부적합하게 된다. 최근에는 압축영역에서의 정보만을 이용해 장면전환점을 검출하는 연구가 많이 진행되고 있으며, 본 논문에서는 압축영역에서 장면전환점을 검출하면서도 보다 빠르고 정확한 검출이 이루어지도록 I픽처 단위의 블록과 P픽처 단위의 내부블록으로 나눈 후 I블록별 검사를 통해 장면전환이 검출된 블록에 대해서 P블록별 검사를 수행하고 최종적으로 B적처까지의 검사를 통해 정확한 장면전환점을 찾는 순차접근법을 제안한다. 순차 접근법은 대부분의 처리가 압축영역에서 이루어지고 또한 블록단위의 결사를 하므로 불필요한 픽처들의 검사과정을 줄여서 보다 빠른 장면전환점 검출이 가능하다 순차접근법은 빠른 처리속도와 함께 정확한 검색이 가능하도록 최적의 알고리즘을 사용하고 있다.