• Korean Journal of Occupational Health Nursing
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• v.31 no.2
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• pp.66-76
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• 2022

Purpose: This study aimed to explore the constructs and context of hospital nurses' organizational silence. Methods: In-depth interviews were conducted with 17 nurses in small-middle general hospitals as well as big university hospitals. We then derived the key themes using grounded theory method. Results: Nine themes and 30 sub-themes were derived: "Willing to be recognized for performance rather than saying", "Getting used to the hard-to-speak climate", "Face the reality that does not change when said", "Complicated situation that prevents self-regulating decision-making", "Conflicts that are difficult to confront", "Unfair responsibilities that I want to evade", "Leaders who don't support me", and "Being blocked in communication". Consequently, the nurses learned to adopt a climate of silence and "learned organizational silence" behavior. They experienced that prosocial silence was essential for obtaining approval as a member of the group, and defensive silence for protecting themselves in the hierarchical structure and unfair responsibilities. Acquiescent silence originated from a futile relationship with their supervisors, one-way communications, and the unsupportive management system, in which three types of silence appeared sequentially or in combination with each other. Conclusion: Based on these results, nursing managers should identify the context of nurses' organizational silence and should lessen these silence behaviors.

• Communications for Statistical Applications and Methods
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• v.31 no.5
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• pp.571-584
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• 2024

To identify differentially expressed genes (DEGs), researchers use a testing method for each gene. However, microarray data are often characterized by large dimensionality and a small sample size, which lead to problems such as reduced analytical power and increased number of tests. Therefore, we propose a clustering method. In this method, genes with similar expression patterns are clustered, and tests are conducted for each cluster. This method increased the sample size for each test and reduced the number of tests. In this case, we used a nonparametric permutation test in the proposed method because independence between samples cannot be assumed if there is a relationship between genes. We compared the accuracy of the proposed method with that of conventional methods. In the simulations, each method was applied to the data generated under a positive correlation between genes, and the area under the curve, power, and type-one error were calculated. The results show that the proposed method outperforms the conventional method in all cases under the simulated conditions. We also found that when independence between samples cannot be assumed, the non-parametric permutation test controls the type-one error better than the t-test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.158-164
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• 2012

Heterogeneous Network and CSG cell are hot issues in the 3GPP LTE/LTE-Advanced system. In this paper, we analyze the system information measurement methods which are essential for handover to CSG cell. Since there have been no sufficient discussion about this problem, we present and analyze five possible solutions. Moreover, we propose a novel solution to reduce system information measurement delay. In the proposed Autonomous Measurement with Parallel Small Gap(AMPSG) method, the UE measures system information of neighbor cells in a parallel manner. As a result, the proposed method shows better delay performance. Therefore, the proposed AMPSG method can reduce handover delay since the UE have to measure the system information of neighbor cells before CSG handover decision.

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.99-105
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• 2022

We have evaluated the performance of an all-optical automatic gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) to suppress the optical signal fluctuation induced by atmospheric turbulence in terrestrial free-space optical communication systems. In our measurements, the input power into the EDFA was set to be -30 dBm and -10 dBm to operate the amplifier in the small-signal and saturation regions, respectively. The fluctuations in the optical signal were emulated with an acousto-optic modulator driven with a sinusoidal voltage. From the measured results, we have found that an all-optical AGC EDFA could suppress the optical signal fluctuation effectively, as long as the EDFA operated in the small-signal region with a high feedback amplified spontaneous emission (ASE) power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.668-676
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• 2012

In this paper, on the assumption that MPI collective communication function is converted into a group of point-to-point communication functions in the transaction level, an algorithm that optimizes broadcast, scatter and gather function among MPI collective communication is proposed. The MPI hardware engine that operates the proposed algorithm was designed, and it was named the OCC-MPE (Optimized Collective Communication Message Passing Engine). The OCC-MPE operates point-to-point communication by using the standard send mode. The transmission order is arranged according to the algorithm that proposes the most frequently used broadcast, scatter and gather functions among the collective communications, so the whole communication time is reduced. To measure the performance of the proposed algorithm, the OCC-MPE with the Bus Functional Model (BFM) based on SystemC was designed. After evaluating the performance through the BFM based on SystemC, the proposed OCC-MPE is designed by using VerilogHDL. As a result of synthesizing with the TSMC $0.18{\mu}m$, the gate count of each OCC-MPE is approximately 1978.95 with four processing nodes. That occupies approximately 4.15% in the whole system, which means it takes up a relatively small amount. Improved performance is expected with relatively small amounts of area increase if the OCC-MPE operated by the proposed algorithm is added to the MPSoC (Multi-Processor System on a Chip).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1277-1284
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• 2011

Today, many applications use 80 port, which is a basic port number of HTTP protocol, to avoid a blocking of firewall. HTTP protocol is used in not only Web browsing but also many applications such as the search of P2P programs, update of softwares and advertisement transfer of nateon messenger. As HTTP traffics are increasing and various applications transfer data through HTTP protocol, it is essential to identify which applications use HTTP and how they use the HTTP protocol. In order to prevent a specific application in the firewall, not the protocol-level, but the application-level traffic classification is necessary. This paper presents a method to classify HTTP traffics based on applications of the client-side and group the applications based on providing services. We developed an application-level HTTP traffic classification system and verified the method by applying the system to a small part of the campus network.

• Journal of Communications and Networks
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• v.17 no.5
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• pp.453-462
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• 2015

Body area networks (BANs) have emerged as an enabling technique for e-healthcare systems, which can be used to continuously and remotely monitor patients' health. In BANs, the data of a patient's vital body functions and movements can be collected by small wearable or implantable sensors and sent using shortrange wireless communication techniques. Due to the shared wireless medium between the sensors in BANs, it may be possible to have malicious attacks on e-healthcare systems. The security and privacy issues of BANs are becoming more and more important. To provide secure and correct association of a group of sensors with a patient and satisfy the requirements of data confidentiality and integrity in BANs, we propose a novel enhanced secure sensor association and key management protocol based on elliptic curve cryptography and hash chains. The authentication procedure and group key generation are very simple and efficient. Therefore, our protocol can be easily implemented in the power and resource constrained sensor nodes in BANs. From a comparison of results, furthermore, we can conclude that the proposed protocol dramatically reduces the computation and communication cost for the authentication and key derivation compared with previous protocols. We believe that our protocol is attractive in the application of BANs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.557-566
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• 2008

Some types of network nodes such as mobile network node, mobile access point, and ad-hoc network node can be relocated frequently and, by the nature of its usage, are deployed over broad area. In this environment, the network topology is changed constantly since even the manager node as well as the managed nodes can leave or join the management network frequently. The many of existing network management technologies are mostly for small sized and homogeneous networks with static topologies and not proper for the mobile network devices. In this paper, employing peer-to-peer (P2P), the secure group communication techniques, and simple network management protocol (SNMP), we propose a highly secure and available management technique that can be used to manage the mobile network nodes through insecure management network such as the Internet. The proposed technique is implemented to show that it is practically usable.

• Communications for Statistical Applications and Methods
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• v.31 no.1
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• pp.1-35
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• 2024

The assumption of homoscedasticity is one of the most crucial assumptions for many parametric tests used in the biological sciences. The aim of this paper is to compare the empirical probability of type I error and the power of ten parametric and two non-parametric tests for homoscedasticity with simulations under different types of distributions, number of groups, number of samples per group, variance ratio and significance levels, as well as through empirical data from an agricultural experiment. According to the findings of the simulation study, when there is no violation of the assumption of normality and the groups have equal variances and equal number of samples, the Bhandary-Dai, Cochran's C, Hartley's Fmax, Levene (trimmed mean) and Bartlett tests are considered robust. The Levene (absolute and square deviations) tests show a high probability of type I error in a small number of samples, which increases as the number of groups rises. When data groups display a nonnormal distribution, researchers should utilize the Levene (trimmed mean), O'Brien and Brown-Forsythe tests. On the other hand, if the assumption of normality is not violated but diagnostic plots indicate unequal variances between groups, researchers are advised to use the Bartlett, Z-variance, Bhandary-Dai and Levene (trimmed mean) tests. Assessing the tests being considered, the test that stands out as the most well-rounded choice is the Levene's test (trimmed mean), which provides satisfactory type I error control and relatively high power. According to the findings of the study and for the scenarios considered, the two non-parametric tests are not recommended. In conclusion, it is suggested to initially check for normality and consider the number of samples per group before choosing the most appropriate test for homoscedasticity.

• Journal of The Korean Association For Science Education
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• v.37 no.6
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• pp.1005-1014
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• 2017

Focusing on the role of the science museum as an institution to improve the scientific literacy of the public, this study investigated public perception and behavior about science museum to know how much science museums affect the public by using social media big data analysis. For this purpose, we extracted texts containing 'science museum' in Naver blogs and Twitter, analyzed them by using network, frequency, co-ocurrence, and semantics analysis and compared them with the results in English speaking countries. As a result, blogs were mainly concerned with science museum among parents who have young children, while in Twitter posts from many students who visited as a group appeared. Therefore, the Korean public used science museum mainly as a space for children's experience, and in this case, programs and exhibitions of science museums are perceived positively. On the other hand, students who visited as a group showed some negative emotions. The result of comparison with the cases of foreign countries in terms of the function of the third generation science museum such as communications with the science museum and the public and the participation of the public in science, the Korean public hardly mentioned the scientific contents, words related to communications such as 'argue', and curators or staff after visiting the science museum. In contrast to many verbs related to meaningful activities such as 'learn', 'participate', 'listen', 'read', 'ask', 'think' appeared in English, only a small number of verbs include 'ask' and 'thin' appeared in Korean. Therefore, science museum need to improve impression, communicating with public, and involving activity with impact and variety after visit.