• Molecules and Cells
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• v.37 no.4
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• pp.337-344
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• 2014

Adipose-derived stem cells represent a type of mesenchymal stem cells with the attendant capacity to self-renew and differentiate into multiple cell lineages. We have performed a microarray-based gene expression profiling of osteogenic differentiation and found that the transcription factor Sox11 is down-regulated during the process. Functional assays demonstrate that down-regulation of Sox11 is required for an efficient differentiation. Furthermore, results from forced expression of constitutively-active and dominant-negative derivatives of Sox11 indicate that Sox11 functions as a transcriptional activator in inhibiting osteogenesis. Sox11 thus represents a novel regulator of osteogenesis whose expression and activity can be potentially manipulated for controlled differentiation.

• The Korean Journal of Archival Studies
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• no.55
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• pp.235-273
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• 2018

The National September 11 Memorial is the institution that collects, assesses, arranges, uses, exhibits, and preserves collections related to the terror attack on September 11, 2001 (9/11), and the explosion incident at the World Trade Center (WTC) on February 26, 1996. After the 9/11 incident, various groups, including the LMDC and the PANYNJ, have participated in the establishment of this organization. Since its initial establishment, the necessity for memorial institutions and detailed characteristics had been discussed in meetings to gather citizens' opinions. Furthermore, the enactment of the 9/11 Memorial Act has secured the institution's stable operation and management. To properly manage disaster-related collections, a just agreement among the citizens and the government should be made to arrive at rational decision-making. This instution can provide answers regarding those ways. Moreover, managing disaster-related collections should be discussed as an important means of remembering, preserving memories, educating, revealing the truth, and preparing academic information and sources. As a result, collaborative governance in records management after a disaster is expected.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.205-208
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• 2007

The IEEE 802.11 is a MAC protocol which has been standardized by IEEE for Wireless Local Area Networks (WLANs). In the IEEE 802.11 WLANs, network nodes experiencing collisions on the shared channel need to backoff for a random period of time, which is uniformly selected from the Contention Window (CW). This contention window is dynamically controlled by the Binary Exponential Backoff (BEB) algorithm. However, the BEB scheme suffers from a fairness problem; some nodes can achieve significantly larger throughput than others. This paper proposes a new backoff algorithm for the IEEE 802.11 DCF scheme. This algorithm uses the hop count for considering fairness. It causes flows with high hop count to generate short backoff interval than those with low hop count, thus getting high priority. Therefore, when a collision occurs, the modified IEEE 802.11 DCF assigns higher priority to flow to be close to a destination.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1175-1180
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• 2009

Frame Aggregation is a promissing technology for improving MAC throughput in IEEE 802.11n. In IEEE 802.11n, two frame aggregation schemes, Aggregate MSDU (A-MSDU) and Aggregation MPDU (A-MPDU), are defined. In this paper, we analyze the performance the two-level frame aggregation scheme where A-MSDU and A-MPDU are combined. We develop the analytical model for the two-level frame aggregation scheme and present numerical results on the effect of bit error rate, aggregation size, and the number of nodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.473-476
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• 2009

Frame Aggregation is a promissing technology for improving MAC throughput in IEEE 802.11n. In IEEE 802.11n, two frame aggregation schemes, Aggregate MSDU (A-MSDU) and Aggregate MPDU (A-MPDU), are defined. In this paper, we analyze the performance the two-level frame aggregation scheme where A-MSDU and A-MPDU are combined. We develop the analytical model for the two-level frame aggregation scheme and present numerical results on the effect of bit error rate, aggregation size, and the number of nodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10A
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• pp.816-822
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• 2011

This paper provides the performance measurement and analysis of Wireless LAN IEEE 802.11 in a mobile environment. The performance of IEEE802.11b/g and IEEE802.11p that is designed for Vehicle-to-Vehicle(V2V) communication is measured and analyzed. Diameter of communication, link access time and delay are measured as vehicle's speed varies. Also, the performance is checked in a situation that the load to network varies. In conclusion, the futher research topics are discussed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.141-151
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• 2004

According to the improvemnent of electronic commerce, the requirements of security devices are becoming increasingly pervasive. The security API must design easily and securely to support a compatibility feature between security devices. It is chosen the PKCS #11 interface by RSA Labs that shows the compatibility and extensibility standards of many application product and implementation, and supported KCDSA mechanism which is a korean digital signature standard. And the PKCS #11 security API defines new key management function which provides more secure key management ability. We suggest the object attributes and templates of KCDSA private and public key object, generate and verify digital signature using KCDSA mechanism. The PKCS #11 supporting KCDSA mechanism is designed, implemented using C-Language, tested a performance, and analyzed the security and compatibiltiy feature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.996-1002
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• 2009

The EDCA scheme in IEEE 802.11 MAC protocols was adopted to support QoS of each traffic. The impact of legacy DCF stations on EDCA voice service is studied using extensive simulations. The maximum number of voice sessions are obtained in cases that IEEE 802.11b and IEEE 802.11a physical layers are used.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6639-6643
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• 2015

Background: Prostate cancer is a major concern of public health. Microvascular density (MVD) is one of the prognostic markers for various solid cancers. Matrix metalloproteinase 11 (MMP11) plays an important role in angiogenesis and changes in its expression level are known to be associated with tumor progression and clinical outcome. Aim: To investigate the relationship between MVD and MMP11 expression in prostatic adenocarcinoma tissues. Materials and Methods: The expression levels of MMP11 and MVD were analyzed immunohistochemically for 50 specimens of prostatic adenocarcinoma. Results: MMP11 was mainly expressed in stromal cells but rarely seen in epithelial cells. Mean MVD was $36/mm^2$, and it was correlated significantly only with bone metastases. MVD was also significantly correlated with MMP11 expression (r=0.29, p=0.044). Conclusions: MMP11 may alter the stromal microenvironment of prostate cancer to stimulate tumor angiogenesis.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.337-343
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• 2009

Purpose: ((R)-1-(2-chlorophenyl)-N-1-[$^{11}$C]methyl-N(1-propyl)-3-isoquinoline carboxamide ((R)-PK11195) is a specific ligand for the peripheral type benzodiazepine receptor and a marker of activated microglia, used to measure inflammation in neurologic disorders. We report here that a direct and simple radiosynthesis of [$^{11}$C](R)-PK11195 in mild condition using NaH suspension in DMF and one-step loop method. Materials and Methods: (R)-N-Desmethyl-PK11195 (1 mg) in DMSO (0.1 mL) and NaH suspension in DMF (0.1 mL) were injected into a semi-prep HPLC loop. [$^{11}$C]methyl iodide was passed through HPLC loop at room temperature. Purification was performed using semi-preparative HPLC. Aliquots eluted at 11.3 min were collected and analyzed by analytical HPLC and mass spectrometer. Results: The labeling efficiency of [$^{11}$C](R)-PK11195 was 71.8$\pm$8.5%. The specific activity was 11.8:$\pm$6.4 GBq/$\mu$mol and radiochemical purity was higher than 99.2%. The mass spectrum of the product eluted at 11.3 min showed m/z peaks at 353.1 (M+1), indicating the mass and structure of (R)-PK11195. Conclusion: By the one-step loop method with the [$^{11}$C]CH3l automated synthesis module, [$^{11}C$](R)-PK11195 could be easily prepared in high radiochemical yield using NaH suspension in DMF.