• Journal of Information Processing Systems
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• v.14 no.4
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• pp.904-915
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• 2018

We demonstrate how social media content can be used to predict the unemployment rate, a real-world indicator. We present a novel method for predicting the unemployment rate using social media analysis based on natural language processing and statistical modeling. The system collects social media contents including news articles, blogs, and tweets written in Korean, and then extracts data for modeling using part-of-speech tagging and sentiment analysis techniques. The autoregressive integrated moving average with exogenous variables (ARIMAX) and autoregressive with exogenous variables (ARX) models for unemployment rate prediction are fit using the analyzed data. The proposed method quantifies the social moods expressed in social media contents, whereas the existing methods simply present social tendencies. Our model derived a 27.9% improvement in error reduction compared to a Google Index-based model in the mean absolute percentage error metric.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2305-2307
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• 2001

Generally, The modeling method for the mathematical model is mdeled by using the physical laws and the system identification. In this paper, The arago's disk system of the operating principle of induction motors is selected as an example for identification. The system transfer function is derived from input/output data through experiment. Model is estimated by using ARX, ARMAX, BJ, OE model structure and compared each other.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.75-76
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• 2016

The relationship of widely used Open circuit Voltage (OCV) versus State of Charge (SOC) is critical for any reliable SOC estimation technique. However, the hysteresis existing in all type of battery which has been come to the market leads this relationship to a complicated one, especially in Lithium Iron Phosphate (LiFePO4) battery. An accurate model for hysteresis phenomenon is essential for a reliable SOC identification. This paper aims to investigate and propose a method for hysteresis modeling. The SOC estimation is done by using Extended Kalman Filter (EKF), the parameter of the battery is modeled by Auto Regressive Exogenous (ARX) and estimated by using Recursive Least Square (RLS) filter to tract each element of the parameter of the model.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.701-704
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• 2015

해시함수는 사회 전반에 걸쳐 무결성 및 인증을 제공하기 위하여서 사용하는 함수로써 암호학적으로 중요한 함수이다. 본 논문에서는 2014년 국가보안기술 연구소에서 개발한 해시함수 LSH를 하드웨어적인 구현이 아닌 소프트웨어적인 구현을 수행하였고 또한 Intel CPU 상에서 동작하는 SIMD 기법인 SSE를 이용하여 LSH 알고리즘의 최적화 구현을 수행한다. 고속해시함수 LSH 알고리즘에서 사용하는 주 연산은 ARX(Addition Rotation, Xor)연산으로 SIMD를 적용하기에 용이한 구조로 되어 있다. 본 논문에서는 기존 32 비트 단위의 연산을 수행하는 LSH 알고리즘을 SIMD를 이용하여 128비트 단위의 연산을 수행 하도록 개발하였다. 그 결과 Intel Xeon CPU에서 SIMED를 적용한 결과 적용하지 않은 LSH 알고리즘보다 최대 2.79배의 성능의 향상을 확인 할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.161-164
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• 2020

경량 암호는 컴퓨팅 파워가 부족한 저사양 프로세서를 위해 개발되었다. CHAM은 국산 경량 암호 중 하나로, 세 가지의 규격을 제공하며 ARX 구조를 사용한 암호이다. CHAM 발표 이후, 라운드 수를 조절하여 성능을 향상시킨 Revised CHAM이 제안되었다. 기존 CHAM은 8-bit AVR 프로세서 상에서 최적 구현이 이루어졌지만, 최신 기술인 Revised CHAM은 해당 구현물이 존재하지 않는다. 따라서 8-bit AVR 프로세서를 대상으로 Revised CHAM-64/128을 최적 구현하여 최상의 성능으로 연산이 진행되도록 한다. 본 논문에서는 최적 구현에 사용한 기법들을 소개하며, 기존에 제안된 기법과 성능 비교를 통해 본 기법의 우수함을 서술한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.97-99
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• 2022

대규모 양자컴퓨터가 등장하면 기존 암호체계가 더 이상 안전하지 않을 것이라 예상한다. 양자 알고리즘인 Grover's brute-force 알고리즘은 대칭키 암호에 대한 attack을 가속화 시켜 보안강도를 감소시킨다. 따라서 양자컴퓨터의 가용 자원이 암호공격에 필요한 자원에 도달했을 때, 공격 대상 암호가 깨지는 시점으로 보고 있다. 많은 선행 연구들은 암호를 양자회로로 구현하여 공격에 필요한 자원을 추정하고 암호에 대한 양자 강도를 확인하였다. 본 논문에서는 이러한 연구동기로 ARX 구조의 SIMECK 경량암호에 대한 양자회로를 처음으로 제안한다. 우리는 SIMECK 양자회로에 대한 최적의 양자회로 구현을 제시하고 각 함수의 동작을 설명한다. 마지막으로 SIMECK 양자회로에 대한 양자자원을 추정하고 SIMON 양자회로와 비교하여 평가한다.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.486-491
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• 2008

This paper describes a model identification method that has been applied to a commercial 12-inch RTP (rapid thermal processing) equipment with an ultimate aim to develop a high-performance advanced controller. Seven thermocouples are attached on the wafer surface and twelve tungsten-halogen lamp groups are used to heat up the wafer. To obtain a MIMO balanced state space model, multiple SIMO (single-input multiple-output) identification with highorder ARX models have been conducted and the resulting models have been combined, transformed and reduced to a MIMO balanced state space model through a balanced truncation technique. The identification experiments were designed to minimize the wafer warpage and an output linearization block has been proposed for compensation of the nonlinearity from the radiation-dominant heat transfer. As a result from the identification at around 600, 700, and $800^{\circ}C$, respectively, it was found that $y=T(K)^2$ and the state dimension of 80-100 are most desirable. With this choice the root-mean-square value of the one-step-ahead temperature prediction error was found to be in the range of 0.125-0.135 K.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.246-254
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• 1996

Since the mid of 1980's, cultivation area and production of Ganoderma lucidum have been increased annually in Korea. However, the presence of a fungal disease has become a major limiting factor in the cultivation of Ganoderma lucidum, causing a serious economic loss. The present study was carried out to isolate and identify the pathogenic fungus to Ganoderma lucidum. Several fungi isolated from the wood logs showing typical symptoms were tested whether they are pathogenic to Ganoderma lucidum or not by cross-pairing culture method, flask inoculation method, and wood log inoculation method. The pathogenic fungus produced ascomata. Mature ascomata was spherical, dark, thick-walled, $45{\sim}95\;{\mu}m$ diameter. Asci were thin-walled, evanescent when mature, disintegrate early. Ascospores were spherical, hyaline, glaborous, thick-walled, refractive, $3.6{\sim}4.3\;{\mu}m$ in size. Conidiophores soon became abundantly septate and broke up into arthrospores, which are cylindrical, $3{\sim}6\;{\mu}m$ long and $3{\sim}4\;{\mu}m$ wide. Based on the observations under dissecting microscope, light microscope and scanning electron microscope, teleomorph and anamorph of the pathogenic fungus were identified as Xylogone sphaerospora Von Arx & Nilsson and Sporendonema purpurascens (Bonordon) Mason & Hughes, respectively. X. sphaerospora is first reported as a pathogenic fungus of Ganoderma lucidum.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.349-356
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• 2018

This paper attempts to develop a connection model based on FE analysis that can be applied to the evaluation of earthquake fragility of Steel Storage Racks lacking research in Korea. In order to accomplish this goal, shaking table tests, modal tests, and various member tests (8 case, push-over test) for structural members have been conducted to understand the behavior of steel storage racks. Based on the experimental results, detailed modeling of the joints was conducted using the NX-Nastran program in order to develop a connection model for Steel storage racks to be applied to the seismic vulnerability assessment. Especially, surface to surface contact element and spring element are applied to simulate the connection between the column member and the beam member connected by the simple latch method. Spring element model developed and applied ARX (Auto Regressive eXogenous) based mathematical model. The simulation results based on the FE model showed excellent reliability with a mutual error rate of less than 8% when compared with the member test results. As a result, it was confirmed that the FE model based connection model developed in the study can be applied to the analytical model for the seismic vulnerability assessment of Steel storage racks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.3
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• pp.401-410
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• 2023

In this paper, we propose optimization methods for implementing SPARKLE, one of the NIST LWC finalists, on a 64-bit ARMv8 processor. The proposed methods consist of two approaches: an implementation using ARM A64 instructions and another using NEON ASIMD instructions. The A64-based implementation is optimized by performing register scheduling to efficiently utilize the available registers on the ARMv8 architecture. By utilizing the optimized A64-based implementation, we can achieve speeds that are 1.69 to 1.81 times faster than the C reference implementation on a Raspberry Pi 4B. The ASIMD-based implementation, on the other hand, optimizes data by parallelizing the ARX-boxes to perform more than three of them concurrently through a single vector instruction. While the general speed of the optimized ASIMD-based implementation is lower than that of the A64-based implementation, it only slows down by 1.2 times compared to the 2.1 times slowdown observed in the A64-based implementation as the block size increases from SPARKLE256 to SPARKLE512. This is an advantage of the ASIMD-based implementation. Therefore, the ASIMD-based implementation is more efficient for SPARKLE variant block cipher or permutation designs with larger block sizes than the original SPARKLE, making it a useful resource.