• Clean Technology
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• v.30 no.3
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• pp.267-275
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• 2024

Lithium-ion batteries (LIBs) have attracted significant attention as potential energy storage solutions due to their high energy density, minimal self-discharge, extended cycle life, and absence of memory effects. However, conventional LIBs use graphite as the anode material and as a result struggle to meet the increasing demand for higher energy density because of the low theoretical capacity of graphite. In order to enhance Li storage capacity and address the current limitations of LIBs, this study designed and analyzed SnO₂ nanoflakes/CNF, which is an advanced anode material with a unique hierarchical structure synthesized via a facile method involving incipient wetness followed by annealing. The in-situ formed SnO₂ nanoflakes improve the electrolyte accessibility and shorten the ion and electron transport pathways, thereby enhancing the reaction kinetics. Additionally, the CNF matrix enhances the electrical conductivity, accelerates electron transport, and mitigates volume changes. The integrated SnO₂ nanoflakes/CNF cell demonstrated outstanding cycling performance and excellent rate capability, achieving a notable reversible capacity of 636 mAh g^-1 after 100 cycles at 0.1 C. This study provides valuable insights into the design of high-efficiency anode materials for the advancement of high-performance LIBs.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.163-167
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• 2007

For numerical analysis of a tidal flow, a two-dimensional hydrodynamic model is developed by solving the nonlinear shallow-water equations. The governing equations are discretized explicitly with a finite difference leap-frog scheme and a first-order upwind scheme on adaptive hierarchical quadtree grids. The developed model is verified by applying to prediction of tidal behaviors. The calculated tidal levels are compared to available field measurements. A very reasonable agreement is observed.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.358-360
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• 2001

In Integrated Services Internet the Resource Reservation Protocol (RSVP) provides a signaling mechanism for end to end QoS. In this paper, we propose a novel scheme using a Hierarchical Mobile Agents Tree (HMAT) based on the definition of new option called QoS Object Option (QOO) in order to improve the efficiency during handoff in Integrated Services Internet. Mobile agents are required to manage QOO, resource reservation and other mobility related basks un behalf of mobile hosts. This scheme is based on Mobile IPv6.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.370-375
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• 1992

This paper deals with the scheduling and simulation for FMC(Flexible Manufacturing Cells). In order to achieve CIM, there is a critical need to link factory level and machine level. The primary functions performed by this link for all jobs issued to the shop floor and cell include short-term scheduling and dynamic operational scheduling. Here, hierarchical control structure is introduced to define these functions. And Intelligent scheduling through expert module is adopted for efficiency of FMC operation. Computer simulation reveals that expert scheduling method is better than heuristics in various performance index.

• Communications for Statistical Applications and Methods
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• v.7 no.3
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• pp.687-698
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• 2000

An identification method is proposed in order to detect more than one outlying cells in multi-way contingency tables. The iterative proportional fitting method is applied to get expected values of several suspected outlying cells. Since the proposed method uses minimal sufficient statistics under quasi log-linear models, expected counts of outlying cells could be estimated under any hierarchical log-linear models. This method is an extension of the backwards-stepping method of Simonoff(1988) and requires les iteration to identify outlying cells.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1668-1676
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• 1997

The wireless communication network is evolving toward the Personal Communication System to provide various multimedia services. In order to accomplish this goal, the effective schemes are required which can dynamically utilize the limited wireless resources based on traffic characteristics of each services. This paper proposes a novel call admission control scheme for the hierarchical macrocell/microcell structured PCS. It is based on the bandwidth reservation procedure performed in the macrocell or neighboring microcell. Its effectiveness is investigated by simulation.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.215-220
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• 2021

As the role of robots expands, flexible task planning methods are attracting attention from various domains. Many task planning frameworks are introduced to efficiently work in a wide range of areas. In order to work well in a broad region with multiple robots, various communication conditions should be controlled by task planning frameworks. However, few methods are proposed. In this paper, we propose mission planning methods according to the communication status of robots. The proposed method was verified through experiments assuming different communication states with a multi-robot system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.925-930
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• 2000

The Problem of allocating paths is very significant in order to transmit a large amount of various data on the ATM network. Therefore, selecting an optimal path among available paths between the a source node and a target node has been researched. Alternate paths designed in previous PNNI routing is not considered on the group-occupation so that traffic congestion happens, when errors occur in the network which consists of a hierarchical network architecture extendable to a large network, We propose the Top-Down algorithm considering an average of the occupation among the groups reported from a leader node in each group and minimizing a traffic congestion

• The KIPS Transactions:PartD
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• v.12D no.6 s.102
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• pp.863-868
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• 2005

Hardware and software codesign framework called PeaCE(Ptolemy extension as a Codesign Environment) was developed. It allows to express both data flow and control flow which is described as fFSM which extends traditional finite state machine. While the fFSM model provides lots of syntactic constructs for describing control flow, it has a lack of their formality and then difficulties in verifying the specification. In order to define the formal semantics of the fFSM, in this paper, firstly the hierarchical structure in the model is flattened and then the step semantics is defined. As a result, some important bugs such as race condition, ambiguous transition, and circulartransition can be formally detected in the model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.419-426
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• 2018

An useful and effective design method for the gas identification system is presented in this paper. The proposed gas identification system adopts hierarchical structure with two level rule base combining fuzzy sets with rough sets. At first, a hybrid genetic algorithm is used in grouping the array sensors of which the measured patterns are similar in order to reduce the dimensionality of patterns to be analyzed and to make rule construction easy and simple. Next, for low level identification, fuzzy inference systems for each divided group are designed by using TSK fuzzy rule, which allow handling the drift and the uncertainty of sensor data effectively. Finally, rough set theory is applied to derive the identification rules at high level which reflect the identification characteristics of each divided group. Thus, the proposed method is able to accomplish effectively dimensionality reduction as well as accurate gas identification. In simulation, we demonstrated the effectiveness of the proposed methods by identifying five types of gases.