Earticle

공공기관, 대학 전산실, 도서관 및 무인민원발급기 등 공용 PC 환경에서는 사용자가 문서를 열람하거나 출력한 후 PDF 파일을 삭제하지 않아 개인정보가 노출되는 사례가 지속적으로 발생하고 있다. 기존 데이터 유출 방지(DLP) 기술은 이메일 전송, USB 저장매체 복사 및 클라우드 업로드 등 외부 반출 과정의 정보 유출 방지에 초점을 두고 있어 시스템 내부에 남겨진 잔존 파일에 의한 개인정보 노출 문제에는 효과적으로 대응하지 못한다. 본 연구에서는 공용 PC 환경에서 잔존 PDF 파일로 인한 개인정보 노출을 방지하기 위한 경량 개인정보 사전 탐지 시스템을 제안한다. 제안 시스템은 PDF 문서로부터 텍스트를 추출한 후 정규표현식 기반 탐지 기법을 적용하여 전화번호, 이메일, 주민등록번호 및 학번 등의 개인정보를 실시간으로 분석한다. 또한 향후 자동 암호화 및 접근통제 기능과 연계 가능한 확장형 구조를 적용하였다. 100개의 PDF 문서를 대상으로 성능을 평가한 결과, Precision 0.96, Recall 0.93, F1-score 0.94를 기록하였으며 평균 처리시간은 12ms/PDF로 나타났다. 또한 BERT 기반 탐지 모델과 비교하여 우수한 처리 속도와 자원 효율성을 확인하였다. 연구 결과는 공용 PC 환경의 개인정보 보호 수준 향상을 위한 실용적인 경량 보안 기술로 활용될 수 있음을 보여준다.

Shared PC environments, such as public service kiosks, university computer labs, libraries, and self-service certificate issuance systems, frequently expose users to privacy risks caused by residual PDF files left on systems after viewing or printing documents. Conventional Data Loss Prevention (DLP) solutions primarily focus on preventing data leakage during external transmission processes, including email transfers, USB storage copying, and cloud uploads, and thus have limitations in addressing privacy exposure caused by residual files within systems. This study proposes a lightweight PDF-based personal information pre-detection system to prevent privacy exposure from residual files in shared PC environments. The proposed system extracts text from PDF documents and employs regular expression–based detection techniques to identify sensitive information, including phone numbers, email addresses, resident registration numbers, and student identification numbers, in real time. Furthermore, the system is designed with an extensible architecture that can be integrated with automatic encryption and access control mechanisms. Experimental evaluations using 100 PDF documents achieved a Precision of 0.96, Recall of 0.93, and F1-score of 0.94, with an average processing time of 12 ms per PDF document. Comparative experiments with a BERT-based detection model demonstrated superior processing speed and resource efficiency of the proposed approach. The results indicate that the proposed system can serve as a practical and lightweight security solution for enhancing privacy protection in shared computing environments.

The use of electronic documents has rapidly increased in recent decades and the PDF is one the most commonly used electronic document formats. A scanned PDF is an image and does not actually contain any text. For the vision–impaired user who is dependent upon a screen reader to access this information, this format is not useful. Thus addressing PDF accessibility through assistive technology has now become an important concern. PDF layout analysis provides precious formatting information that supports PDF component classification. This classification facilitates the tag generation. Accurate tagging produces a searchable and navigable scanned PDF document. This paper describes several practical segmentation methods which are easy to implement and efficient for PDF layout analysis so that the scanned PDF document can be navigated or searched using assistive technologies.

The paper presents the advanced radiometric calibration method, called the lRCM (Iterative Radiometric Calibration Method), in order to avoid an operational constraint (solar source) for calibration. The IRCM assumes that an optical instrument is equipped with a filter assembly which consists of same band filters with different transmission ratios. Given all the noise sources (including the artificial one caused by the filters) of an image sensor, the noncentral ${\chi}^2$ distribution of the output result is induced by the approach of a noise PDF (Power Density Function). Finally, the radiometric calibration problem is transformed into equating two independent relations for the image sensor gains through the specified distribution.

The paper clarifies all the noise sources of a CMOS image sensor, with which the GOCI (Geostationary Ocean Color Imager) is equipped, and analyzes their contribution to a nonlinear image sensor model. In particular, the noise PDF (Probability Density Function) is derived in terms of sensor-gain coefficients: a linear and a nonlinear gains. As a result, the relation between the noise characteristic and the sensor gains is studied.

This study proposed the Probability Density Function (PDF) interpolation technique to evaluate the seismic fragility curves as a function of the return period. Seismic fragility curves have been developed as a function of seismic intensities such as peak ground acceleration, peak pound velocity, and pseudo-velocity spectrum. The return period of design earthquakes, however, can be more useful among those seismic intensity measurements, because the seismic hazard curves are generally represented with a return period of design earthquakes and the seismic design codes also require to consider the return period of design earthquake spectrum for a specific site. In this respect the PDF interpolation technique is proposed to evaluate the seismic fragility curves as a function of return period. Seismic fragility curves based on the return period are compared with ones based on the peak ground acceleration for the bridge model.

염해에 노출된 콘크리트 구조물의 내구수명 평가는 매우 중요하므로 최근들어 결정론적 및 확률론적 방법을 통하여 내구수명을 평가하는 시도가 이루어지고 있다. Fick's 2nd 법칙에 근거한 내구수명 평가방법은 표면 염화물량과 확산계수의 시간의존성을 고려하여 합리적인 설계를 수행하고 있으나, 확률론적 방법에서는 이러한 영향이 고려되지 않고 있다. 본 논문에서는 시간에 따라 증가하는 표면염화물량을 유효 표면염화물량으로 고려한 뒤 시간의존성 확산계수를 고려하여 내구적 파괴확률을 도출할 수 있는 해석기법을 제안하였다. 표면염화물에 도달하는 기간을 10~30년으로, 표면염화물량을 $5.0{\sim}10.0kg/m^3$으로 변화시키면서 내구적 파괴확률을 평가하고 내구수명의 변화를 분석하였다. 제안된 기법은 결정론적 내구수명 평가방법의 해석조건을 동일하게 적용시키면서 설계인자의 확률 변동성을 고려할 수 있으므로 과다한 설계를 방지함으로서 합리적인 설계기법으로 적용할 수 있다.

Recently durability design based on deterministic or probabilistic method has been attempted since service life evaluation in RC(Reinforced Concrete) structure exposed to chloride attack is important. The deterministic durability design contains a reasonable method with time effect on surface chloride content and diffusion coefficient, however the probabilistic design procedure has no consideration of time effect on both. In the paper, a technique on PDF(Probability of Durability Failure) evaluation is proposed considering time effect on diffusion and surface chloride content through equivalent surface chloride content which has same induced chloride content within a given period and cover depth. With varying period to built-up from 10 to 30 years and maximum surface chloride content from $5.0kg/m^3$ to $10.0kg/m^3$, the changing PDF and the related service life are derived. The proposed method can be reasonably applied to actual durability design with preventing conservative design parameters and considering the same analysis conditions of the deterministic method.

In this paper we derive the pdf for the envelope of the received signal in Nakagami fading environment. Then, using this pdf we analyze the performance of Noncoherent FSK and DPSK in Nakagami fading channel. For ASK it is difficult to find the threshold value in Nakagami fading we confine our discussion in the special case of m=1, which is in Rayleigh fading.

This paper deals with accuracy of accumulated fatigue damage estimation using stochastic fatigue analysis method based on Rayleigh PDF. From full scale measurement data on an 8100TEU container vessel, zero-order spectral moments for wave- and vibration-induced energy spectral densities are determined on the probability level of 99%. 80 simulation cases in total are prepared according to the variation of ratio of zero-order spectral moments and center frequency of vibration ESD. By using inverse Fourier transformation and rainflow cycle counting for the combined ESD of wave and vibration, exact fatigue damages are derived. Fatigue damages in frequency domain based on Rayleigh PDF show large conservativeness compared to exact fatigue damages in times domain. The main cause of the excessive conservativeness is analyzed by two aspects: ratio of zero crossing and peak frequencies and ratio of initial zero order spectral moments and zero order spectral moments from rainflow stress range distributions. Finally, a guideline of applicability of Rayleigh PDF is proposed for wide band processes.