• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.11
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• pp.900-904
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• 2011

In this paper, we investigated an anomalous hump phenomenon under the positive bias stress in p-type LTPS TFTs. The devices with inferior electrical performance also show larger hump phenomenon. which can be explained by the sub-channel induced from trapped electrons under thinner gate oxide region. We can confirm that the devices with larger hump have larger interface trap density ($D_{it}$) and grain boundary trap density ($N_{trap}$) extracted by low-high frequency capacitance method and Levinson-Proano method, respectively. From the C-V with I-V transfer characteristics, the trapped electrons causing hump seem to be generated particularly from the S/D and gate overlapped region. Based on these analysis, the major cause of an anomalous hump phenomenon under the positive bias stress in p-type poly-Si TFTs is explained by the GIDL occurring in the S/D and gate overlapped region and the traps existing in the channel edge region where the gate oxide becomes thinner, which can be inferred by the fact that the magnitude of the hump is dependent on the average trap densities.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.19-25
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• 2002

In this paper, a laboratory investigation was carried out to change the geotechnical properties of clayey soil with quicklime and rice husk ash for surplus soil strength improvement. The organic content of soils is 8.67%, 6.45% and 3.84% respectively. The geotechnical properties of treated soil were evaluated by a series of laboratory unconfined compression test, consolidation test and etc. The test results indicated that the presence of RHA enhanced the efficiency of lime stabilization. Especially, the increase in strength is very high at the first stage, while the significant improvement occurs in a sample C with organic content of 3.84%. These results can be identified by X-ray diffraction(XRD) and scanning electron microscope(SEM). The results of consolidation test indicate that the presence of RHA with lime reduces the properties of swelling of soil. Thus, it was verified that the addition of RHA is more effective than using only lime for soil stabilization.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.77-83
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• 2014

As the interest on the air pollution is gradually risen up at home and abroad, their vehicle emission regulations have been reinforcing by steps. PM regulation was also reinforced 4times for the last 13years and has been applied to SI vehicles after EURO 5. Additionally, knowing that small particles of PM can easily penetrate deep into lungs PM number was added on the regulation from EURO5+ and is applied to CI vehicles. Also, PN regulation is going to be applied to SI vehicles. But, because the regulation is appled to only a general test mode of each countries that is performed at $25{\pm}5^{\circ}C$, it is unclear whether the regulation can work on the other ambient temperature conditions or not. In this paper, to know that exhaust emission characteristics at the special conditions CI vehicles(CRDi w, w/o DPF) were tested using 5-cycle mode, NEDC mode at 5-ambient temperatures (35, 25, 0, -7 and -15) and the exhaust emission test results were discussed. The results show that the vehicle with DPF emits much low PM(and PM number) on all of the test mode. However, NOx of the other mode was emitted higher than regulation mode. Also. NOx was sharply increased according to decreasing Ambient Temperature.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.7
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• pp.45-52
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• 2019

In recent years, there has been a demand for a residential supply model that can actively and flexibly cope with various housing demands in the changing paradigm of public rental housing. This study focuses on the two-step supply system that has been studied in Japan. It was used to examine and analyze cases to recommend a supply plan that can be used for domestic public rental housing. In more detail, the literature review of the two-step supply system discloses that four types by supply methods (A-1, A-2, B-2, and C-2) and four types of relationship (construction and management combine entities type, management entity type, construction entity type, a separated entity type) can be categorized. In addition, from the actual case study, it revealed that the way of linking and supplying activities among the entity can have a great influence on "ease of supply (supply)", "diversity of housing demand (diversity)," and "quality of construction (construction)". "Ease of supply (supply)" refers to whether the construction entity is separated, and the owner is a manager. "Diversity" refers to whether the management subject is separated, and if the owner is also the constructor or the manager. "Construction" is whether the management entity is connected and managed by the management entity and can be evaluated in "Good", "Middle", and "Bad" level. As a summary, even if the existing public rental housing in Korea can be separated into a skeleton and infill system, the result suggested that it has a limitation on response to residential demand. In addition, the paper was able to propose an improved plan to make the infill as a secondary operator.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.171-178
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• 2003

Differentiated Services (DiffServ) is a technique to provide Quality of Service (QoS) in an efficient and scalable way. However, current DiffServ specifications have limitations in providing the complete QoS management framework and its implementation model. This paper proposes a policy-based QoS management model that supports DiffServ policies for managing QoS of DiffServ networks. The management model conforms to Model-View-Controller (MVC) architecture, and is based on Enterprise JavaBeans (EJBs) technologies. In our model, high-level DiffServ QoS policies are represented as valid XML documents with an XML Schema and are translated to low-level EJB policy beans in the EJB-based policy server. The routing topology and role information required to define QoS policies is discovered by using SNMP MIB-II, and the QoS policy distribution and monitoring is accomplished by using SNMP DiffServ MIB.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.227-234
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• 2006

In this paper, we propose a window based resource reservation scheme to minimize an waste bandwidth due to resource reservation in mobile networks. Specially, this scheme decides a proper timing to reserve resource by using the number of movement, which is provided by the differentiated handoff estimation model, among inner regions. In the previous resource reservation scheme[6], it requests a resource reservation to neighboring cells as soon as a mobile host enters or creates into a cell. But, after a proper time based on the number of movements in the differentiated handoff estimation model passes, the proposed scheme requests a resource reservation to neighboring cells. Because of this reason, it can improve resource utilization on mobile networks. And, this scheme differentiates resource reservation according to a request ratio for resource reservation to each neighboring cell. Also, this scheme improves resource reservation acceptance rate and bandwidth utilization.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.744-751
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• 2006

In case of the Soil Nail System applied to a slope, effects of vibrations from blasting, earthquake and creep of long term behaviors cause reductions of adhesion between grout and soil-nail. There are some reports of nail's pull-out failure by those reasons. In this paper it is suggested that the Cone Nailing System is enable to diminish effects of vibrations and creep. In this study on Cone Nailing System, the cones are installed to each nail by 2m. By such installing cones, the adhesion between nail and grout will increase and the long term creep behavior will decrease. In this study, the centrifuge test is performed to understand the behaviors of the Cone Nail System. For the centrifuge test, the soil tank is 52cm in width, 17cm in length and 35cm in height. In comparison with general soil nail, the centrifuge test of general soil nail(without cone) is performed equally. Additionally, the interface between cone nail and soil through the pull-out test is applied to FLAC 2D version 3.3. and the evaluation of application for the Cone Nail System in slope is performed.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.907-916
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• 2005

RMCP is an application layer multicast protocol and was established as a standard by ITU-T Also, RMCP includes a scheme which can statically construct a multicast tree. In this paper, we propose a QoS based tree construction scheme which can dynamically construct a multicast tree. And this scheme shows more superior performance than the static tree scheme of RMCP in terms of start-up delay and user requirement QoS. This scheme consists of a best-fit method using multiple sub-net groups which are satisfied a user requirement QoS and a first-fit method using one sub-net group which has maximum transmission bandwidth. In simulation result, two proposed methods are superior to the existing static tree scheme.

• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.15-21
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• 2015

In this paper a prediction method of GHP performance is proposed for increasing design accuracy. Two compressors with different capacity and 2311cc gas engine are used for prediction and the target capacity of GHP is 25HP. For predicting GHP performance at first the operation points are randomly selected and then as compared with compressor performance date and heat exchanger characteristic, more accurate operating points are decided through recursive calculation. Lastly engine performance date is used for calculating gas consumption volume. Predicting heating mode performance of GHP, evaporator is separated to the two section of absorbing heat in outdoor air and in engine. From the experimental results, it was found that the simulation model is good for the predicting GHP efficiency and the difference of predicted and measured efficiency is less than 5%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.74-77
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• 2004

[ $HfO_2$ ] dielectric layers were grown on the p-type Si(100) substrate by metalorganic molecular beam epitaxy(MOMBE). Hafnium $t-butoxide[Hf(O{\cdot}t-C_4H_9)_4]$ was used as a Hf precursor and Argon gas was used as a carrier gas. The thickness of the layers was measured by scanning electron microscopy (SEM) and high-resolution transmission electron measurement(HR-TEM). The properties of the $HfO_2$ layers were evaluated by X-ray diffraction(XRD), high frequency capacitance-voltage measurement(HF C-V), current-voltage measurement(I-V), and atomic force measurement(AFM). HF C-V measurements have shown that $HfO_2$ layer grown by MOMBE has a high dielectric constant(k=19-21). The properties of $HfO_2$ films are affected by various process variables such as substrate temperature, bubbler temperature, Ar, and $O_2$ gas flows. In this paper, we examined the relationship between the $O_2/Ar$ gas ratio and the electrical properties of $HfO_2$.