• ETRI Journal
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• 제25권5호
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• pp.379-386
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• 2003

This paper presents the design of a narrow-band channel filter and its group-delay equalizer for a Ka-band satellite transponder. We used an 8th order channel filter for high selectivity with an elliptic-integral function response and an inline configuration. We designed a 2-pole, reflection-type, group-delay equalizer to compensate for the steep variation of the group-delay at the output of the channel filter, keeping the thermal stability at ${\pm}7$ ns of group-delay variation at the band edges over 15-55$^{\circ}C$. We devised a new tuning technique using short-ended dummy cavities and used it for tuning both the filter and equalizer; this removes the necessity of additional tuning after the cavities are assembled. Through measurement, we demonstrate that the group-delay-equalized filter meets the equipment requirements and is appropriate for satellite input multiplexers.

• 방송공학회논문지
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• 제15권3호
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• pp.407-413
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• 2010

주파수 재사용률 1을 사용하는 상향링크 셀룰러 시스템의 동적채널할당 (DCA : Dynamic Channel Allocation) 방법에서는 신규호가 채널 할당을 요구할 때 신규호의 SINR (Signal to Interference and Noise Ratio)이 요구된 SINR 보다 작거나 할당할 채널이 부족한 경우에 신규호 차단이 발생한다. 이러한 차단된 신규호에 대한 추가적인 채널할당을 위하여 인접한 셀에서 채널을 가져오게 된다. 이 경우에 동일 채널 간섭 (CCI: Co-Channel Interference)이 발생하게 되고 이로 인해 기존 호의 SINR이 저하되어 기존 호에 대한 채널 재할당을 해야 하는 경우가 생기게 된다. 따라서 신규호 블록율이 증가할수록 인접한 셀에서 채널을 가져오는 경우의 수를 증가시킴으로써 채널 재할당 과정은 복잡한 연산과정이 필요한 NP-hard 문제가 된다. 그 문제를 해결하기 위하여 본 논문에서는 차단된 신규호를 감소시킴으로써 추가적인 채널할당을 위하여 인접한 셀에서 채널을 가져오는 횟수를 감소시키고 그 결과로 채널 재할당 횟수가 감소되어 복잡한 연산과정을 피할 수 있는 Group Search-based DCA 방법을 제안한다. 제안한 방법은 신규호의 차단율을 감소시키기 위하여 신규호에 대한 채널할당시 단말이 속해 있는 셀뿐만 아니라 그 주변의 셀까지를 한 그룹으로 묶어서 채널 탐색 범위를 확장하는 방법을 사용한다. 시뮬레이션 결과에서 제안한 Group Search-based DCA가 탐색 범위를 단말이 속한 셀로 한정하는 Single Search-based DCA보다 신규호 차단률과 시스템 수율 성능을 향상시킴을 확인할 수 있었다.

• 한국기계가공학회지
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• 제18권11호
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• pp.103-108
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• 2019

The cooling rate and the uniformity of mold temperature, in the injection molding process, possess great influences on the productivity and quality of replications. The conformal cooling channel, which is of a uniform spacing from the mold cavity by the metal additive manufacturing process, receives much attention recently. The purpose of this study is to develop a mold core with a curved conformal cooling channel for a pottery-shaped thick-wall cosmetic container through the hybrid method of direct metal tooling (DMT) process. In this study, we design a mold core that contains the curved cooling channel for the container. A method that divides the cavity is proposed and the DMT process is carried out to form the curved cooling channel. The test mold core, with the curved conformal cooling channel, has been fabricated by the proposed method to confirm the feasibility of the design concept. We show that no leakage is observed for the additive manufactured test mold core, and its physical properties demonstrate that it can be sufficiently used as the injection mold core.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.113-116
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• 2000

The effect due to group delay and non linear characteristics in high speed data satellite channel was represented in this paper. Based on the modeling of group delay and non linear characteristics the performance was analyzed in ka band satellite channel. The group delay and non-linear characteristics in high speed data transmission severely affect the system performance. The more Eb/No is required to satisfy the required system performance. The optimum operating points of HDR satellite transmission system are implemented by considering analyzed results for channel characteristics

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1063-1064
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• 2011

• The Korean Journal of Physiology and Pharmacology
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• 제7권3호
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• pp.131-142
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• 2003

We have studied mutant forms of Kir2.1 in which an aspartate residue (D172), important for gating by intracellular polyamines, is replaced by one of three basic residues (Arg, Lys or His). Such channels are highly selective for $K^+$, but show inward rectification that is a shallow function of voltage compared with that found in wild type. This inward rectification occurs with a reduced affinity for spermine and persists in the absence of polyamines. Though the unitary current-voltage relation shows some inward rectification, it is insufficient to account for that seen under whole cell recording. Channels open and shut under single channel recording, and changes of $P_{open}$ appear to generate inward rectification. In D172H, the reduction in affinity for spermine is greater when His is protonated at low $pH_i$. The effective valency for spermine is reduced from $3.09{\pm}0.07$ in wild type to $1.95{\pm}0.09$ in D172H at $pH_i$ 6.3. In the presence of dual mutants of Kir2.1, where E224 is also replaced, spermine affinity becomes undetectable. However, channels still show inward rectification and open and shut under hyper- and depolarisation, respectively. We suggest that Kir2.1 channel are able to undergo conformation changes; these changes may be important physiologically in generating inward rectification, the normal parameters of which are set by the binding of polyamines such as spermine.

• 한국통신학회논문지
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• 제38B권3호
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• pp.207-215
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• 2013

본 논문은 효율적인 무선 AMI 네트워크를 위한 채널 할당 및 스케줄링 기법에 관한 것이다. AMI 시스템에서, 제안하는 다중채널 클러스터 네트워크는 NC(Network Coordinator)와 CDA(Clustered Data Aggregator) 간의 통신 채널을 네트워크 채널로 정의 하고, CDA와 OMD(Out Meter Display), SMD(Smart Meter Device) 간의 통신채널을 그룹 채널로 정의한다. 네트워크 채널과 그룹채널이 혼합된 다중채널 클러스터 기반의 AMI 네트워크는 물리적/논리적 수용가 채널 클러스터링을 통해서 관리의 효율성을 증대하고, 인접 클러스터간 구별되는 채널 사용을 통한 검침 데이터의 신뢰성을 증대한다. 또한 다중채널 클러스터 기반의 채널할당을 통하여 데이터의 빠른 수집이 가능하며 검침망의 크기를 증가시킨다.

• 유통과학연구
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• 제19권7호
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• pp.75-85
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• 2021

Purpose: This study is focused on analyzing the key reasons why One-brand Shop has been shrinking and Multi-brand shop is rising from the perspective of the trend changes of customer behavior and distribution channel in the Korean cosmetic market. The purpose of this study is to examine the factors influencing the attractiveness of cosmetics distribution channels from a store perspective and a consumer perspective. Research methodology: This study conducted a survey to define the factors that influence the attractiveness of cosmetics distribution channels. A total of 300 samples were investigated. Results: The store factors that influence the attractiveness of the cosmetics distribution channel were product quality, shopping convenience, and store accessibility in the group of single-brand store preferences, and product diversity and store experience in the group of multi-brand store preferences. Conclusions: Core competing factors of One-brand shop include product value, shopping convenience and accessibility. In contrast, Multi-Brand shops offer core competing factors of diversified product portfolio and shop function experience. A new trend has been found that the customer segments of the price-oriented group and the pleasure-oriented group have become the mainstream segments in the Korean cosmetic market. In conclusion, Multi-brand Shops are suggesting better overall customer experiences in terms of distribution channel attractiveness and customer values.

• ETRI Journal
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• 제25권6호
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• pp.523-526
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• 2003

This letter presents an approximation of the outage probability of the pilot channel that can be used for CDMA cell planning. The approximation can determine system parameters for soft handover in IS-95-based cellular CDMA downlink design. Computer simulations show that our analytical results agree with empirical results.

• Journal of electromagnetic engineering and science
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• 제3권2호
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• pp.140-146
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• 2003

In this paper, the design of a channel filter and its group-delay-and-amplitude equalizer is carried out for the Ka-band satellite transponder subsystem. The 8th order dual-mode filter is employed for high selectivity around the band-edges with an elliptic-integral function response and has an in-line configuration. The 2-pole, reflection-type, group-delay equalizer is designed and manufactured to reduce the group-delay and amplitude variation, which can be large for such a high order filter. It is noted that in both the filter and equalizer, adopting the dual-mode coupling mechanism leads to less mass and volume. Through measurement, the performance of the realized group-delay-equalized filter is shown to meet the equipment requirements and to be appropriate for the satellite input multiplexer.