• Journal of Preventive Medicine and Public Health
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• 제33권1호
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• pp.51-55
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• 2000

Objectives . In large-scale field trials, randomization by cluster is frequently used because of the administrative convenience, a desire to reduce the effect of treatment contamination, and the need to avoid ethical issues that might of otherwise arise. Cluster randomization trials are experiments in which intact social unit, e.g., families, schools, cities, rather than independent individuals are randomly allocated to intervention groups. The positive correlation among responses of subjects from the same cluster is in matter in cluster randomization. This thesis is to compare the results of three randomization methods by standard error of estimator of treatment effect. Methods : We simulated cholesterol data varing the size of the cluster and the level of the correlation in clusters and analyzed the effect of cholesterol-lowering agent. Results : In intra-cluster randomization the standard error of the estimator of treatment effect is smallest relative to that in inter-cluster randomization and that in individual randomization. Conclusions : Infra-cluster randomization is the most efficient in its standard error of estimator of treatment effect but other factor should be considered when selecting a specific randomization method.

• 응용통계연구
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• 제1권2호
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• pp.61-65
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• 1987

확률화(randomization)는 각 실험단위를 처리에 배치할 때 반드시 지켜야 할 실험계획의 큰 원칙이다. 확률화는 각 처리 간의 비교에 있어 실험외적 요인의 효과를 상쇄시켜 주며 또한 통계적 추론을 더욱 뒷받침하여 준다.

• Clinics in Shoulder and Elbow
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• 제16권1호
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• pp.58-62
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• 2013

서론: 최근 임상 연구와 논문의 활성화 속에 높은 신뢰도를 보장하는 방법을 따르는 예들은 아직 많지 않다. 이에 연구의 편향을 최소화하는 무작위 추출의 개념과 바른 방법에 대해 알아보고자 한다. 대상 및 방법: 최근까지 발표된 무작위 추출에 대한 문헌 고찰을 통해 무작위 추출의 기본 개념 및 필요성을 정리하고 바른 무작위 추출을 위한 조건 및 무작위 추출의 종류별 방법들(단순 무작위 추출, 순열화 블록 무작위추출, 계층화)에 대해 살펴 보았다. 결과 및 결론: 무작위 추출은 임상 연구에서 편향을 줄이고 통계적 검사를 이용한 자료 분석의 보장된 유효성을 제공한다. 이렇듯 보다 신뢰도 높은 연구 결과를 도출해 낼 수 있는 방법인 무작위 추출에 대한 개념 재정립 및 바른 무작위 추출 방법의 제안은 연구자들에게 꼭 필요한 과정이라 할 수 있겠다.

• Journal of Acupuncture Research
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• 제24권1호
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• pp.127-135
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• 2007

Objectives: To evaluate the methodological quality of Korean Acupuncture Clinical trials Methods : Two independent researchers reviewed 12 protocols of Acupuncture clinical trials which were conducted in Korea 2006. Also, Survey Principal Investigator of those was conducted. We compare the results of protocol review with investigator reponses of actual practice. Quality assessment consisted of 5 items including random sequence generation, randomization method, allocation concealment, subject blinding, assessor blinding. Results : Randomization was performed using the proper procedure to insure that treatment assignment is unbiased and concealed from subjects in all clinical trials, According to protocols, 6(50%) of 12 clinical trials used computer-generated random numbers, 6(50%) remaining trials didn't describe the randomization method. Also all trials used appropriate randomization methods on the basis of the survey results: 8 trials used computer-generated random number, 2 used random table. Of 7 protocols in which allocation concealment was stated, 5(71%) reported appropriate method (Calling a central office or statisticians, Sealed opaque envelopes). However according to survey, 5(42%) of 12 trials used inappropriate allocation concealment (Keeping a master randomization list and referring to when subject entered the trial). In addition, the result of protocol review and survey response was not coincident in 5(42%) trials. Subject blinding was conducted in all except 1 clinical trials. Although 11(92%) of 12 trials were conducted using assessor blinding in actual practice, only 7(58%) reported that in protocol. Conclusion : Although randomization and blinding were conducted adequately, allocation concealment was used inadequately, Not only appropriate allocation concealment, but also every quality assessment item including randomization, blinding should be stated in more detail in protocol.

• 정보처리학회논문지C
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• 제14C권5호
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• pp.439-452
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• 2007

본 논문에서는 랜덤화 기법을 이용한 프라이버시 보존형 데이터 마이닝(PPDM) 기술에 대하여 논한다. 계산 효율성 때문에 실용화 되지 못하고 있는 안전한 다자간 계산(SMC) 기반 PPDM은 현재의 컴퓨팅 환경에서는 실용성 없는 다분히 이론적인 것이다. 그래서 우리는 실용적인 PPDM 기술에 집중하여 가장 널리 사용되고 있는 랜덤화 기법에 대한 연구 결과를 소개한다. 특히, 랜덤화를 이용한 실용적인 PPDM 분야에서 가장 중요한 프라이버시 측도 개념을 심도 있게 분석하였으며, 연관규칙 마이닝에서의 프라이버시 보호 기술에 초점을 맞춘다. Evfimievski 등이 제안한 select-a-size 범주에 속하는 새로운 랜덤화 작용소인 binomial-selector 개념을 제안하고, 적절한 파라미터를 찾기 위한 시뮬레이션 결과를 제시한다. 기존의 cut-and-paste 랜덤화 작용소는 아이템 집합이 큰 경우에는 매우 비효율적이며 복원된 지지도의 분산이 크다는 단점을 지니고 있다. 여기에서 제안하는 binomial-selector 랜덤화 작용소는 cut-and-paste 작용소가 갖는 단점들을 보완한다.

• Journal of the Korean Statistical Society
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• 제16권2호
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• pp.113-116
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• 1987

The role of randomization is examined with regard to the Simpson's paradox. When the sample size n is large, it is known that the randomization is powerful in preventing the Simpson's paradox. In the present study, the question is whether is performs well for small n.

• Journal of the Korean Statistical Society
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• 제15권1호
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• pp.26-30
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• 1986

Basu (1980) examined Fisher Randomization Test (FRT) of matched pair experimental data with critical point of view. Additionally, Lane (1980) pointed out that "the experimenter may be interested in a weaker notion of equality between two treatments, " than the notion of equality which FRT relies on. In this study, a randomization test is developed so that it can test a weaker hypothesis of equality. equality.

• Journal of Computing Science and Engineering
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• 제5권3호
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• pp.169-182
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• 2011

Privacy preserving microdata publication has received wide attention. In this paper, we investigate the randomization approach and focus on attribute disclosure under linking attacks. We give efficient solutions to determine optimal distortion parameters, such that we can maximize utility preservation while still satisfying privacy requirements. We compare our randomization approach with l-diversity and anatomy in terms of utility preservation (under the same privacy requirements) from three aspects (reconstructed distributions, accuracy of answering queries, and preservation of correlations). Our empirical results show that randomization incurs significantly smaller utility loss.

• Journal of information and communication convergence engineering
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• 제8권6호
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• pp.651-654
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• 2010

In this paper, we propose two power randomization schemes for the random beamforming (RBF) based MIMO systems in cellular downlink. In the proposed system, a BS randomizes not only the pre-coding matrix but also the power allocation matrix, while the conventional RBF system allocates an equal power to each transmit stream. The proposed water-filling based power randomization scheme (Scheme-I) is proper in the low SNR values and the proposed random-power based randomization scheme (Scheme-II) is proper in the high SNR values. The proposed system with the power randomization outperforms the conventional RBF system which allocates the same power for each data stream.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권1호
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• pp.120-144
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• 2023

With the expansion of digital communication networks, a considerable number of randomization techniques have been invented and implemented to enhance the different data transmission algorithms' levels of security. Steganography is among the data transmissions techniques used to hide secret data. Nowadays, several randomization techniques have been used in steganography to elevate the security of transmitted data. Unfortunately, the majority of these techniques lack some simplicity, efficiency, and flexibility, in addition to other limitations. This research presents a new randomization technique called Rand-Stego. Rand-Stego could be applied/practiced over any steganography technique. It provides simplicity and efficiency and elevates the security level. Examples of implementing the proposed technique on some steganography algorithms will be explored. The proposed and current techniques will be compared. The obtained results show Rand-Stego's superiority in terms of efficiency and flexibility when compared to the current techniques.