• Journal of Biosystems Engineering
• /
• 제22권4호
• /
• pp.451-458
• /
• 1997

In order to investigate the compost process and the evaporating phenomenon, a rotary reversing compost system has been tested in swine fm. In the summer season, the compost temperature were varied in the range of 50~$60^{\circ}C$ and the ash content has been increased to 12.8% showing in average of 24.7% at the end of phase. In the winter season, the compost temperature were varied in the range of 40~$57^{\circ}C$ and the ash content has been increased to 8.5% showing in the average of 18% at the end of phase. In summer the compost facility could handle all of the animal waste, but in winter it could not handle 1/4~1/3 of the animal excrement. The needed sawdust by this method could be reduced to 1/3 than that of the mixing method at the beginning of compost process.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2019년도 춘계학술대회
• /
• pp.10-14
• /
• 2019

IoT(Internet of Things: 사물인터넷)의 보급이 시작되면서 보안 위협 또한 증가하고 있는 추세이다. IoT에 관련된 보안 사고는 재물적 피해는 물론 나아가서는 인간에게 직접적인 위험을 줄 수도 있으므로 이러한 문제들을 방지하기 위해서 IoT 장치의 보안 설비는 매우 중요하다고 할 수 있다. 본 논문은 IoT 장치의 정의와 보안사고 사례, 아키텍쳐, 개방형 무선 네트워크를 사용할 때 발생할 수 있는 보안 문제점에 대해서 서술했다.

• 대한수학회보
• /
• 제60권2호
• /
• pp.443-460
• /
• 2023

A binary linear code is said to be a ℤ₂-double cyclic code if its coordinates can be partitioned into two subsets such that any simultaneous cyclic shift of the coordinates of the subsets leaves the code invariant. These codes were introduced in [6]. A ℤ₂-double cyclic code is called reversible if reversing the order of the coordinates of the two subsets leaves the code invariant. In this note, we give necessary and sufficient conditions for a ℤ₂-double cyclic code to be reversible. We also give a relation between reversible ℤ₂-double cyclic code and LCD ℤ₂-double cyclic code for the separable case and we present a few examples to show that such a relation doesn't hold in the non-separable case. Furthermore, we list examples of reversible ℤ₂-double cyclic codes of length ≤ 10.

• Structural Engineering and Mechanics
• /
• 제32권4호
• /
• pp.501-516
• /
• 2009

This paper aims to study the large deflections of variable-arc-length elastica subjected to the terminal forces (e.g., axial force and torque). Based on Kirchhoff's rod theory and with help of Euler parameters, the set of nonlinear governing differential equations which free from the effect of singularity are established together with boundary conditions. The system of nonlinear differential equations is solved by using the shooting method with high accuracy integrator, seventh-eighth order Runge-Kutta with adaptive step-size scheme. The error norm of end conditions is minimized within the prescribed tolerance ($10^{-5}$). The behavior of VAL elastica is studied by two processes. One is obtained by applying slackening first. After that keeping the slackening as a constant and then the twist angle is varied in subsequent order. The other process is performed by reversing the sequence of loading in the first process. The results are interpreted by observing the load-deflection diagram and the stability properties are predicted via fold rule. From the results, there are many interesting aspects such as snap-through phenomenon, secondary bifurcation point, loop formation, equilibrium configurations and effect of variable-arc-length to behavior of elastica.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 추계학술대회 논문집
• /
• pp.208-212
• /
• 2008

Gas hydrate has been paid attention to study for because: 1) it can be considered as a new energy resources; 2) one of reasons causing the instability of sea floor slope and 3) a factor to the climate change. Bottom simulating reflector (BSR) defined as seismic boundary between the gas hydrate and free gas zone has been considered as the most common evidence in the seismic reflection data for the gas hydrate exploration. BSR has several characteristics such as parallel to the sea bottom, high amplitude, reducing interval velocity between above and below BSR and reversing phase to the sea bottom. Moreover, instantaneous attribute properties such as amplitude envelop, instantaneous frequency, phase and first derivative of amplitude of seismic data from the complex analysis could be used to analyze properties of BSR those would be added to the certain properties of BSR in order to effectively find out the existence of BSR of the gas hydrate stability zone. The output of conventional seismic data processing for gas hydrate data set in Ulleung basin in the East sea of Korea will be used for complex analyses to indicate better BSR in the seismic reflection data. This result of this analysis implies that the BSR of the analyzed seismic profile is clearly located at the two ways time (TWT) of around 3.1 seconds.

• 수산해양기술연구
• /
• 제57권1호
• /
• pp.45-56
• /
• 2021

In order to understand the tide and current around the sea route of Jinhae and Masan passages, tide measurement and 2D numerical model experiments of tidal current and residual flow were carried out. Tide is composed of 84% of semi-diurnal tide, 11% of diurnal tide and 4% of shallow water tide, respectively. Phase lags of the major components for the tide around the study area have little differences. The flows are reversing on the whole, but have rotational form around Jamdo Island, south of Masan passage in spring tide and Ungdo Island, north of Masan passage in middle and neap tide. Current flows the speed of 50 cm/s in the sea areas near small islands, 5 cm/s in Jinhae harbor, Hangam bay and near Jinhae industrial complex and 20-30 cm/s in Jinhae passage, Budo channel and Masan passage. Tide-induced topographical eddies are formed near small islands, but few eddies exist and the flow rate of less than 5 cm/s tidal residual current formed in Jinhae and Masan passages. The flows in Jinhae and Masan passage give a good condition for a passage into Jinhae and Masan harbor.

• 영어영문학
• /
• 제58권2호
• /
• pp.347-378
• /
• 2012

Holocaust fiction has always raised the moral and aesthetic questions about the nature of mimesis and the literary representation of atrocity. The Holocaust, defying any representation of it, has been considered as unspeakable, unknowable, and incomprehensible. This essay aims to explore Martin Amis's narrative strategies in Time's Arrow to conduct the difficult tasks of re-creating the primal scene and of discovering a moral reality behind the Holocaust. One of the major narrative experiments in Time's Arrow is the time reversal: the story moves from the present of phony innocence to the past of unrelieved horror. Reversing the temporal order of events reverses causality and generates the revision of the morality, ultimately creating the epistemological and ontological uncertainties. Amis's novel is also narrated from the perspective of a double persona of the protagonist who, as a Nazi doctor, participated in the massacre in Auschwitz and then fled to the United States following the war. As almost a self-conscious storyteller, the narrator shares a sense of retrospective guilt with the reader who finally realizes that the Holocaust was a world turned upside down morally. Amis's postmodern narrative strategies are unusual enough to warrant a new way of representing the Holocaust.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2021년도 춘계학술대회
• /
• pp.434-437
• /
• 2021

Canopen over Ethercat은 산업현장에서 EtherCAT 기반으로 동작하는 Canopen 프로토콜이다. 패킷 스니핑을 통하여 구축된 CoE 시스템의 성능을 분석하기 위해서 Canopen 프로토콜에서 사용하는 Process Data Object의 구성과 그 값의 변화를 분석하는 과정은 필수적이다. 하지만 Canopen의 Data Object는 네트워크를 구성하는 장치에 의존적이기 때문에 wireshark와 같은 패킷 분석 프로그램으로 분석하는데 한계가 있다. 따라서 본 연구에서는 CoE 프로토콜을 분석하여 시스템 구성과 Process Data Object를 유추하는 프로그램을 설계하고 구현하였다.

• 정보보호학회논문지
• /
• 제25권6호
• /
• pp.1465-1475
• /
• 2015

일반적으로 온라인 게임에서 사용하는 치팅 프로그램 탐지 모델은 클라이언트 단의 치팅 흔적을 조사하여 이를 실시간으로 탐지하는 방식과 서버의 누적 로그에 탐지 알고리즘을 적용하여 치팅 유저를 분류하는 서버 단 탐지 모델로 나누어진다. 클라이언트 탐지 모델은 Anti-reversing 기능 제공과 게임 메모리 변조와 같은 다양한 치팅 공격에 대한 탐지가 가능하나, 탐지 모듈이 클라이언트 단에 배포되어 동작하여 분석 및 우회가 가능할 뿐 아니라 오탐지로 인해 기능의 확장에 한계가 있다는 단점이 존재한다. 이로 인해 많은 주목을 받고 있는 서버 로그 분석 탐지모델은 강력한 탐지 및 높은 정확도를 자랑하나, FPS와 같이 저 사양의 쉽고 단순한 접근성을 가진 로그 데이터만으로는 치팅 유저와 일반 유저 사이의 유의미한 차이점을 찾기가 어려워 이를 활용하지 못하는 단점이 존재하였다. 본 논문에서는 상기한 두 탐지 모델의 단점을 보완하기 위해, 클라이언트 단의 게임 보안 솔루션의 로그 정보와 서버 로그를 융합한 실험을 통해 효율적인 탐지 모델을 재설계 하였으며 실제 서비스 중인 FPS 게임에 이를 검증해 보았다.

• Smart Structures and Systems
• /
• 제29권5호
• /
• pp.661-675
• /
• 2022

In this paper, an electric vehicle drives with efficient control and low cost hardware using four quadrant DC converter with Permanent Magnet Direct Current (PMDC) motor fed by DC boost converter is presented. The main idea of this work is to improve the energy efficiency of the conversion chain of an electric vehicle by inserting a boost converter between the battery and the four quadrant-DC motor chopper assembly. Consequently, this method makes it possible to maintain the amplification gain of the 4 quadrant chopper constant regardless of the battery voltage drop and even in the presence of a fault in the battery. One of the most important control problems is control under heavy uncertainty conditions. The higher order sliding mode control technique is introduced for the adjustment of DC bus voltage and mechanical motor speed. To implement the proposed approach in the automotive field, experimental tests were carried out. The performances obtained show the usefulness of this system for a better energy management of an electric vehicle and an ideal control under different operating conditions and constraints, mostly at nominal operation, in the presence of a load torque, when reversing the direction of rotation of the motor speed and even in case of battery chamber failure. The whole system has been tested experimentally and its performance has been analyzed.