• 충청수학회지
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• 제18권1호
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• pp.73-80
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• 2005

The aim of the paper is to study the connectivity and the edge-connectivity of inserted graph I(G) of a graph G with the help of connectivity and the edge-connectivity of that graph G.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.61-64
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• 2002

In this study, It was designed and developed optimal rotary dressing system of centerless grinding using for ferrule machining. Dressing shaft's dropping is calculated by Finite Element Method, and bearing 7206ADB, 7005ADB is selected. Dressing wheel $GC\Box \;200\Box\; G\Box\; m\Box\; V-100^*25^*16$ is selected by pre-research. Also Motor, pulley, belt are selected, 0.4Kw-60Hz, 48.2 mm diameter, 2-5M-730 type, each.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.43-47
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• 1997

A procedure presented in this paper generates test sequences to check the conformity of an implementation with a protocol specification, which is modeled as a deterministic finite state machine (FSM). Given a FSM, a common procedure of test sequence generation, first, constructs a directed graph which edges include the state check after each transition, and produces a symmetric graph G* from and, finally, finds a Euler tour of G*. We propose a technique to determine a minimum-cost tour of the transition graph of the FSM. The proposed technique using Multiple Unique State Signature (MUSS) solves an open issue that one MUIO sequence assignment may lead to two more edges of unit cost being replicated to from G* while an optimal assignment may lead to the replication of a single edge of high cost. In this paper, randomly generated FSMs have been studied as test cases. The result shows that the proposed technique saves the cost 4∼28% and 2∼21% over the previous approach using MUIO and MUSP, respectively.

• 한국포장학회지
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• 제25권3호
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• pp.111-116
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• 2019

Thermal insulation performance of new insulation packaging made of recycled PET nonwoven (thickness : 10 mm) was verified by conducting comparative experiment with an EPS box (thickness : 25 mm) and a double wall corrugated box (thickness : 7 mm). Three ice packs (300 g) were positioned 200 mm above the bottom inside each box, all of which are placed side by side and temperature change of 2 points (5mm under middle icepack and 130 mm under middle icepack) was recorded by data logger (GL-840, Graphtec) for 16 hours under the environment of 29℃. The new packaging box showed 75% higher insulation performance than the EPS box and 180% higher than the corrugated box. In order to figure out the reason for insulation performance difference among boxes, thermal conductivities of each box material were measured using heat flow meter (HFM436 lamda, Netzsch). U-value (thermal conductivity divided by thickness) of EPS was lower than recycled pet nonwoven by 57%, which seemed to be opposite to the result of insulation test of boxes. This was explained by high water vapor transmission rate of EPS (6 times higher than PET insulation) and air pocket effect of PET insulation.

• 한국지반공학회지:지반
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• 제12권5호
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• pp.27-40
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• 1996

박스 구조들은 상.하수도관, 통신 및 전기선로, 도로, 철도 등을 위한 여러가지 목적으로 오래 전부터 많이 사용되어 왔다. 도심지에서는 대부분 지반을 굴착하여 박스 구조물을 설치한 후에 되채움하는 과정을 거친다. 그러나 박스에 작용하는 토압을 위한 기존의 설계법에서는 굴착(또는 되채움)되는 단면의 형상을 고려하지 못하고 있다. 본 연구에서는 매설박스 설계시 굴착되는 단면형상을 고려할 수 있는 새로운 토압이론식을 제안하였다. 이 이론식에 의한 수평토압은 유한요소해석 결과와 비교적 좋은 일치를 보여 주었으나, 기존설계법에 의한 토압은 상당히 과대평가되었다. 박스의 상단면에 작용하는 연직응력의 이론값은 기존 설계법 및 유한요소해석 결과와 거의 유사하였다. 그러나 박스의 바닥면에 작용하는 반발응력은 기초지반의 탄성계수에 따라 크게 좌우되므로, 새로운 이론식은 기초지반이 느슨한 모래인 경우를 제외하면 직접 적용이 어려웠다. 한편, 유한요소해석에 의하면 박스에 작용하는 수평토압은 굴착면의 경사와 굴착저면의 폭에 따라 크게 좌우되었다.

• Journal of Biosystems Engineering
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• 제19권4호
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• pp.358-368
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• 1994

Major factors in reducing the stacking strength of corrugated fiberboard boxes in cold storage or transport conditions are high relative humidity, causing elevated moisture absorption by the boxes. The bottom boxes in a stack will deform to the critical deflection causing agricultural products damage there, and eventually additional deflection will cause box collapse and finally toppling of the stack. The study was conducted to determine the water absorption characteristics and the compressive strength of the corrugated fiberboard boxes being widely used in packaging agricultural products in Korea. The sample boxes for the study were selected from the regular slotted containers (RSC) types, and one was the box used in apple packaging (Box A), another one was the box used in pear packaging (Box B). The corrugated shipping containers were made from a large portion of recycled fibers in Korea, and comparing with Box B, Box A was fabricated from fiberboard which contained more percentage of old corrugated containers (OCC) imported from foreign countries than domestic waste paper. The results obtained from the study were summarized as follows ; 1. Equilibrium moisture content (EMC) of the sample boxes was established after about 20 hours, and the EMC by absorption was lower than that by desorption. The EMC increased with the increasing of relative humidity and with the decreasing of temperature, and the rate of increasing was much higher above the relative humidity of 50%. 2. The maximum compressive strength of Box A was about 100 kgf greater than that of Box B on the same enviromental conditions. The strength of the sample boxes decreased rapidly with the increasing of relative humidity. The effect of relative humidity on the strength was a little higher than that of temperature. 3. As the applied load was progressively increased and a level was reached, the vertical side panels ($L{\times}D$) deflected laterally inwards or outwards. The panels deflected laterally inwards at higher relative humidity. 4. The maximum compressive deflection ratio and the critical deflection ratio of the sample boxes were increased linearly with the increasing of relative hunidity, but trends for its ratios showed inconsistant response to temperature.

• 한국환경과학회지
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• 제29권10호
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• pp.969-979
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• 2020

A numerical simulation was conducted on perfluorooctane sulfonate (PFOS) in the Gwangyang Bay using a multi-box model to estimate the transport of organic chemicals in the coastal environment. The results of the sensitivity analysis on dissolved PFOS and PFOS in Particulate Organic Carbon (POC) indicate that they were most significantly influenced by the adsorption rate, desorption rate, and sinking velocity coefficients. PFOS in phytoplankton was found to be sensitive to bio-concentration and the excretion rate. The results of the mass balance indicate that the standing stocks of PFOS in water, POC, and phytoplankton are 345.55 g, 63.76 g, and 0.11 g, respectively, in the inner part and 149.90 g, 27.51 g, and 0.05 g, respectively, in the outer part. Considering flux in the inner part, adsorption to POC had the highest value among transition paths. The next highest were desorption, outflow to the outer part, and inflow to the inner part. Outflow into the open sea was found to have the highest value for the outer part.

• 대한전자공학회논문지SD
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• 제41권12호
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• pp.67-74
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• 2004

AES는 인터넷 프로토콜의 대칭키 보안 알고리즘으로 널리 사용된다. 무선 내장형 시스템들이 점점 더 전통적인 유선 네트워크 프로토콜을 많이 사용하고 있으므로 이들 무선 내장형 시스템을 위한 저비용 AES 알고리즘 구현은 매우 중요하다. 가장 기본적인 AES 아키텍처는 키 스케줄을 포함하여 20개의 S-box를 사용하는 하나의 cipher 라운드로 구성되어 있다. 암호화는 동일한 라운드를 반복하여 완료된다. 근래에 이 방법의 구현 비용을 더욱 줄이기 위하여 오직 8개의 S-box만 사용하는 folded architecture가 제안되었다. 본 논문에서는 folded architecture를 이용하여 무선 통신 기술을 위한 저비용 AES 구현 구조에 대하여 연구한다. 먼저 folded architecture를 개선하여 16 바이트의 추가적인 상태 메모리 사용을 줄였다. 구현 비용을 더욱 줄이기 위하여 데이터 암호화에 하나의 S-box만 사용하는 single byte architecture를 구현하였다. Single byte architecture는 암호화에 352 클록이 소요된다. FPGA 구현 시 최대 동작 주파수는 40MHz에 도달하였다. 따라서 암호화 속도는 13Mbps 이상으로 3G 무선통신에 충분하다.

• 적정기술학회지
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• 제5권2호
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• pp.82-90
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• 2019

반응표면분석법(Response surface methodology, RSM)의 Box-Benhken Design (BBD) 모델을 사용하여, 350℃로 가열한 골탄의 수중 불소 흡착 조건을 최적화하였다. 최적화 변수로 수온, pH, 접촉시간, 초기불소농도를 선택하였고, Box-Behnken Design에 의한 29회의 매트릭스 실험값으로부터 2차 반응 표면식을 얻었다. 이 반응 모델식의 결정계수(R²)는 0.9249였고 모델의 p-value는 <0.0001로 나타나 실험 변수들이 흡착결과에 매우 유의미한 영향을 미친다는 것을 알 수 있었다. 반응 표면식에 의해 예측된 골탄의 불소 흡착 최적 조건은 수온 39.68℃, pH 6.25, 접촉시간 88.81 min, 초기불소농도 14.64 mgF/L이었으며 이때의 불소 흡착용량(adsorption capacity)은 6.46 mgF/g인 것으로 분석되었다.

• 전산구조공학
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• 제19권2호
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• pp.64-70
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• 2006