김욱성 교수

Liquid crystals (LCs) technology have a well-established history of applications in visible light, particularly in the display industry. However, with the rapid growth in communication technology, LCs have become a topic of current interest for high-frequency microwave (MW) and millimeter-wave (mmWave) applications due to promising characteristics such as tunability, continuous tuning, low losses, and price compatibility. To improve the performance of future communication technology using LCs, i

Abstract Conventional digital learning with 2D videos or simulations on monitors and tablets has limitations in engineering education when covering complex concepts or complicated 3D structures. In response, virtual reality (VR) has been introduced as an immersive method that can enhance learning effectiveness. This study analyzed the impact of VR on overall learning outcomes and understanding of 3D structures in engineering education, comparing it with traditional digital learning approaches. W

We investigated the utility of comprehensive scoring systems for organ failure compared with the duration of extracorporeal life support (ECLS) in predicting survival after heart transplantation. From November 2004 to August 2013, 25 adult patients ultimately underwent heart transplantation while on ECLS. We did not include patients who were younger than 18 years old or patients with extracorporeal ventricular assist devices. Seven patients (28%) died within 1 year after transplantation. The are

Cardiac arrest caused by acute pulmonary embolism is associated with high patient mortality. We reviewed patients who had cardiac arrest caused by acute pulmonary embolism. Between January 2001 and September 2013, we identified 20 patients at our institution with a confirmative diagnosis of acute pulmonary thromboembolism and cardiac arrest. Percutaneous cardiopulmonary support (PCPS) and surgical embolectomy are the standard course of care for patients with shock or cardiac arrest caused by pul

This study is aimed to find a control factor for the marine casualty of fishing vessel by using the risk quantitative method of marine casualty, and sequentially timed event analysis for the reason finding. The result is that collision, sinking, and capsizing took high risk need to be strongly controlled. And the accident reason and control factors distinguished are as follows. The 82.2% of collided fishing vessels have negligence of look out as a immediate cause, while it was judged that underl

Abstract A liquid-crystal (LC)-based floating electrode-free (FE-free) coplanar waveguide (CPW) phase shifter with an additional LC layer is demonstrated for the first time. An LC layer is overlain on the electrodes of the original model; this change increases the amount of electric flux that the proposed structure can confine in the tunable region, and thereby greatly increases the figure-of-merit (FoM) while maintaining the benefits of the simple coplanar structure. We simulated the variations

The aim of this study is to research attributes of fishermen's occupational accidents for investigating the measure of risk control on situational condition in the Korean offshore and coastal fishing vessel. Using data of fishermen's occupational accidents are from National federation of fisheries cooperatives for 2013. The results were as belows; Occupational accident occurrence rate was 29.5‰, slips & trips and struck by object and contact with gear were shown severe occurrence pattern. Occupa

This paper presents an optical see-through head-mounted display (OST-HMD) that can provide a highly immersive augmented reality (AR) environment. Because visibility of objects is degraded by external light and because projection optics cannot represent black color, the reality of AR content is reduced. To solve this problem, we adopted an additional transparent display to adjust the transmittance of exterior light. This adjustment is achieved using a guest-host liquid crystal (GHLC) to provide t

Using a single substrate, we demonstrate a simple two-dimensional (2-D) phase grating cell with an octothorp electrode. Owing to the large spatial phase difference in any direction, the proposed grating cell has a high haze value in the opaque state (76.7%); Moreover, it has the advantages of a one-dimensional (1-D) phase grating cell, such as high fabricability, fast response time, and low operating voltage. Furthermore, the proposed grating cell has a faster response time than the 2-D grating

This study proposed a virtual reality (VR) course that addresses the overall understanding and application of VR technology. After investigating previous studies, we found that two technologies must be applied to design a VR course that fits the latest trends. One is hardware technology dealing with the technical background, while the other is software utilization and development using the merits of VR technology. To accommodate these needs, we designed a VR course consisting of three steps: VR-

Adv. Mater. 2023, 35, 2302474 DOI: 10.1002/adma.202302474 In the originally published article, the version of Figure 9 that was included was not the intended version. Consequently, the figure caption and references and the figure itself do not align. Therefore, the figure is hereby corrected.

A novel technique to enhance the phase shifting range of a liquid crystal (LC)-based, substrate-integrated waveguide (SIW) phase shifter by inserting inductive posts (IPs) is presented for the first time. The IPs inserted in the LC-based SIW phase shifter produce a phase advance based on the relative permittivity of the LC, resulting in an additional differential phase shift. At 28 GHz, the proposed structure with IPs achieves a ratio of maximum differential phase shift (∆ϕmax) to maximum insert