Wonjun Kim

Overlay text brings important semantic clues in video content analysis such as video information retrieval and summarization, since the content of the scene or the editor's intention can be well represented by using inserted text. Most of the previous approaches to extracting overlay text from videos are based on low-level features, such as edge, color, and texture information. However, existing methods experience difficulties in handling texts with various contrasts or inserted in a complex bac

As a means to support the access of massive machine-type communication devices, grant-free access and non-orthogonal multiple access (NOMA) have received great deal of attention in recent years. In the grant-free transmission, each device transmits information without the granting process so that the base station needs to identify the active devices among all potential devices. This process, called an active user detection (AUD), is a challenging problem in the NOMA-based systems since it is dif

Deep learning (DL), a branch of artificial intelligence (AI) techniques, has shown great promise in various disciplines such as image classification and segmentation, speech recognition, language translation, among others. This remarkable success of DL has stimulated increasing interest in applying this paradigm to wireless channel estimation in recent years. Since DL principles are inductive in nature and distinct from the conventional rule-based algorithms, when one tries to use DL technique t

In this letter, we propose a novel method to extract illumination-invariant features for face recognition and verification under varying illuminations. Inspired by the fact that normalized coefficients of the singular value decomposition (SVD) are insensitive to different illumination conditions, we exploit a simple, yet powerful scheme for describing underlying structures of faces, so-called SVD face. In contrast to previous approaches still suffering from the loss of details, our SVD face grea

An important observation in the ultra-reliable and low latency communications is that the size of transmit information is tiny. To support the effective short packet transmission, a sparse vector coding (SVC) scheme where an information is encoded into the positions of the sparse vector was proposed. In this paper, we propose a novel SVC technique further improving the reliability of the short packet transmission. Key idea of the proposed technique is to encode information both in the position a

In recent years, we have witnessed a bewildering variety of automated services and applications involving vehicles, robots, sensors, and machines powered by artificial intelligence (AI) technologies. Communication mechanisms associated with these services are clearly distinct from human-centric methods. One important feature of machine-centric communication is that the amount of information to be transmitted is tiny. In view of the short packet transmission, relying on today's transmission mecha

Major goal of ultra reliable and low latency communication (URLLC) is to reduce the latency down to a millisecond (ms) level while ensuring reliability of the transmission. Since the current uplink transmission scheme requires a complicated handshaking procedure to initiate the transmission, to meet this stringent latency requirement is a challenge in wireless system design. In particular, in the time division duplexing (TDD) systems, supporting the URLLC is difficult since the mobile device has

Ultra-reliable and low-latency communication (URLLC) is a new service category to accommodate emerging services requiring low end-to-end latency. In the 4G LTE/5G NR, it is very difficult to satisfy the URLLC requirements since multiple OFDM symbols are processed as a bundle. In this paper, we propose a novel low-latency packet transmission scheme, referred to as ultra-mini slot transmission (UMST), suitable for the short packet transmission in URLLC scenario. Key idea of the proposed scheme is

As a means to support the access of massive machine-type communication devices, grant-free access and non-orthogonal multiple access (NOMA) have received great deal of attention in recent years. In the grant-free transmission, each device transmits information without the granting process so that the basestation needs to identify the active devices among all potential devices. This process, called an active user detection (AUD), is a challenging problem in the NOMA-based systems since it is diff

Oxide-supported metal catalysts are essential components in industrial processes for catalytic conversion. However, the performance of these catalysts is often compromised in high temperature reaction environments due to sintering effects. Currently, a number of studies are underway with the objective of improving the metal support interaction (MSI) effect in order to enhance sintering resistance by surface modification of the oxide support, including the formation of inhomogeneous defects on th

Massive machine-type communication (mMTC), key component for internet of things (IoT), concerns the access of massive machine-type communication devices to the basestation. To support the massive connectivity, grant-free access and non-orthogonal multiple access (NOMA) have been recently introduced. In the grant-free transmission, each device transmits information without the granting process so that the basestation needs to identify the active devices among all potential devices. This process,

Fifth generation (5G) wireless networks are currently being developed to handle wide variety of use cases. In order to support these cases, new types of requirements other than throughput enhancement have been introduced. One such requirement is to reduce the latency down to a millisecond (ms) level in ultra reliable and low latency communications (URLLC). In case of uplink transmission, supporting this stringent latency requirement is quite challenging and problematic since the scheduling proce

This paper presents a simple, yet powerful local image descriptor, called the histograms of dominant orientations (HDO). The HDO consists of two components, namely the dominant orientation and its coherence, which represents how intensively gradients in the local region are distributed along the dominant orientation. For a given image patch, we incorporate these two components into a 1-D histogram and define it as our HDO descriptor. Compared to previous approaches suffering from the presence of

Future mobile communication systems need to support wide variety of new services and applications. In order to support these, ITU-R introduced new types of use cases. One such use case, called ultra reliable and low latency communication (URLLC), concerns the reduction of latency down to a millisecond level while ensuring the reliability of the transmission. In case of uplink transmission, supporting the stringent latency requirement of URLLC is quite challenging due to a time-consuming and comp