Joongbu University

Mobile ad hoc networks (MANETs) are highly vulnerable to denial-of-service (DoS) attacks because their decentralized operation, rapidly changing topology, and constrained node resources limit the use of heavyweight security mechanisms. This paper presents an Adaptive Clustering and Random-Forest-based Intrusion Detection System (ACRF-IDS), a lightweight intrusion detection framework that combines mobility-aware adaptive clustering with supervised learning to detect network-layer DoS behaviors. Cluster heads are elected using a multi-metric utility (residual energy, link stability, and mobility) to stabilize observations under node movement. Within fixed monitoring windows, cluster heads aggregate routing-, forwarding-, and energy-related features and classify nodes using a Random Forest model; a temporal voting scheme further suppresses transient mobility-induced alarms. Using ns-2.35 simulations with Ad hoc On-Demand Distance Vector (AODV) and both flooding and blackhole DoS scenarios, ACRF-IDS is compared with (i) a static clustering-based threshold IDS, (ii) a non-clustered Support Vector Machine (SVM)-based IDS, and (iii) AIFAODV, which specializes in flooding. Across the evaluated network sizes (4-50 nodes), the proposed method achieves a higher detection rate and F1-score while maintaining a lower false positive rate than the baseline techniques. We additionally quantify network-level impact using PDR, throughput, and routing overhead, showing that ACRF-IDS improves availability under DoS while adding bounded overhead. Future work will extend the evaluation to more diverse attack behaviors and validate the approach in real-world MANET testbeds.

The bascule bridge, which serves to help the movement of ships, has been studied for maintenance and management by various researchers for more than several decades. Since the drawbridge is opened daily or frequently, maintenance is very important, and in particular, a precise study on the vibration sensitivity of each component when opening is required. In the drawbridge section of the Yeongdodaegyo bridge, a small noise was generated inside the machine room at the same time as the drawing work started, so a study was conducted on noise cause analysis for structural safety. To this end, the safety of the drawbridge was evaluated through the current status of the drawbridge, damage to main members, and noise measurement, and the cause of noise was analyzed. In particular, in this study, temperature change during the drawing process of the Yeongdodaegyo Bridge were investigated on temperature variation. As a result of the analysis, noise was generated at the bearing joint of the drawbridge, but it was noise generated inside the machine room and it was judged that there was no problem with the safety of the bridge in terms of vibration and harshness sensitivity. Die Zugbr & uuml;cke, die dem Schiffsverkehr dient, wird seit Jahrzehnten von verschiedenen Forschern hinsichtlich Wartung und Instandhaltung untersucht. Da die Zugbr & uuml;cke t & auml;glich oder h & auml;ufig ge & ouml;ffnet wird, ist die Wartung sehr wichtig. Insbesondere ist eine genaue Untersuchung der Schwingungsempfindlichkeit aller Komponenten beim & Ouml;ffnen erforderlich. Im Zugbr & uuml;ckenabschnitt der Yeongdodaegyo-Br & uuml;cke traten zu Beginn der Zieharbeiten leichte Ger & auml;usche im Maschinenraum auf. Daher wurde eine Studie zur Ursachenanalyse des L & auml;rms im Hinblick auf die strukturelle Sicherheit durchgef & uuml;hrt. Zu diesem Zweck wurde die Sicherheit der Zugbr & uuml;cke anhand ihres aktuellen Zustands, der Sch & auml;den an den Haupttr & auml;gern und der L & auml;rmmessung bewertet und die Ursache des L & auml;rms analysiert. Insbesondere wurden Temperatur & auml;nderungen w & auml;hrend des Ziehvorgangs der Yeongdodaegyo-Br & uuml;cke untersucht. Die Analyse ergab Ger & auml;usche an der Lagerfuge der Zugbr & uuml;cke, jedoch entstanden Ger & auml;usche im Maschinenraum. Es wurde festgestellt, dass hinsichtlich der Schwingungs- und Rauheitsempfindlichkeit keine Sicherheitsprobleme der Br & uuml;cke bestehen.

Ferroelectric optoelectronic devices have attracted growing interest for self-powered photodetection owing to their intrinsic polarization, which can provide a built-in electric field without external bias or chemical doping. However, conventional ferroelectric oxides suffer from wide bandgaps and critical thickness limitations, restricting their applicability in ultrathin, broadband optoelectronic devices. In this work, we construct a van der Waals (vdW) heterointerface composed of p-type tungsten diselenide (WSe2) and ferroelectric alpha-phase indium (III) selenide (alpha-In2Se3), and systematically investigate its interfacial band alignment using X-ray photoelectron spectroscopy technique. Raman measurement and X-ray diffraction analyses were used to confirm the vibrational properties and crystalline phases of WSe2 and alpha-In2Se3, respectively. Quantitative band alignment analysis reveals band offset of 0.83 +/- 0.05 eV and 0.55 +/- 0.05 eV for valence and conduction bands, respectively, establishing a type-II staggered band alignment accompanied by pronounced band bending induced by interfacial dipoles and charge redistribution. Exploiting the established type-II band alignment, a WSe2/In2Se3 pn heterojunction photodetector is designed, exhibiting efficient photovoltaic effect and broadband photoresponse. These results highlight the critical role of interfacial band offset engineering in vdW heterostructures and demonstrate the strong potential of WSe2/In2Se3 vdW heterointerfaces for future self-powered photodetecting devices.

Understanding interfacial band alignment is essential for elucidating charge transport dynamics and guiding the design of heterojunction-based optoelectronic applications. Two-dimensional van der Waals semiconductors offer unique opportunities to engineer interfacial electronic structures owing to their atomically sharp interfaces and reduced dimensionality. In this study, we systematically investigate the interfacial band alignment of a tellurium/molybdenum disulfide (MoS2) van der Waals heterojunction. The crystalline structures and vibrational characteristics of tellurium and MoS2 are confirmed by X-ray diffraction analysis and Raman spectroscopy analysis, respectively. High-resolution X-ray photoelectron spectroscopy (XPS) is conducted to quantitatively define the valence band offset using the Kraut method. The analysis reveals a staggered type-II band alignment at the tellurium/MoS2 interface with valence band offset (0.43 +/- 0.05 eV) and conduction band offset (0.1 +/- 0.05 eV), accompanied by pronounced core-level shifts indicative of interfacial band bending and charge redistribution. The experimentally extracted band offsets provide direct insight into carrier separation and transport behavior across the heterointerface and serve as quantitative design parameters for optoelectronic heterostructures. These results establish tellurium/MoS2 heterojunctions as a well-defined model system for interfacial band alignment studies and highlight the critical role of XPS-based band offset analysis in understanding and engineering van der Waals heterointerfaces.

With the growing trend of online short-form content consumption, the creation and adoption of short-form dramas are similarly on the rise. The user base for these dramas has witnessed a notable increase, particularly in Asia and North America. Given this rapid expansion, their global market impact is anticipated to be substantial. Building upon an extended Technology Acceptance Model (TAM), this study conceptualized users' perceptions by integrating individual and social characteristics to construct a comprehensive research model predicting user attitudes and continuous usage intentions. Data were collected via an online survey administered to short-form drama users to assess their perceptions, attitudes, and intentions regarding the continued use of short-form dramas. The survey results revealed that Perceived Usefulness, Perceived Ease of Use, and Perceived Playfulness of short-form dramas positively influenced user attitudes. Furthermore, these attitudes were found to have a significant positive effect on continued use intentions. This study contributes to a more comprehensive understanding of short-form drama consumption, offering valuable insights into user behavior for drama production teams and related marketers.